Overreacting sarcastic behavior?

Mr.B: What do you have to prove that your religion is scientific, unlike the other religions?

Mr. A: It depends  on the intelligence level of the listener, low levels are unable to believe

Mr.B told Mr.A that he committed the Ad Hominem fallacy 

Mr.A: Ok, I will be silent forever so you could take your time preaching about what science is 

Mr.B spoke some opinions about the difference between science and religion but this instead caused Mr.A to attack Mr.B that Mr.B never accepts anyone's opinion.

Is there a fallacy name that describes Mr.A's behavior?

What do you have to prove that your religion is scientific, unlike the other religions? 

This is an odd question. Perhaps the one who claimed their religion was "scientific" made the odd claim. There can be claims within the religion that are scientific, but that is all. Point is, this seems like a debate that would go nowhere.

It depends on the intelligence level of the listener, low levels are unable to believe 

This sentence is incoherent. Ironic if they are trying seem intelligent. Perhaps they mean that they will present the evidence that their audience is capable of understanding? This makes sense as good communication is about understanding. If someone were to say this to me, I would ask them to assume they are speaking to someone very intelligent, and give me the evidence. What I would expect is some nonsense about quantum physics that they are only pretending to understand. Or in general, they will present nonsense and claim that I am not "intelligent enough" to understand. I have played this game many times before.

I don't see any fallacies in the dialogue you presented. No clear ad hominems. However, if Mr. B made an argument that warranted a response, and Mr. A's response was an attack on Mr. B, that would be an ad hominem (abusive) .

Again, this line of argumentation is odd. If you are Mr. A or Mr. B, I would think about revising the argument/claim to something more clear and specific.

There appear to be a series of non-sequiturs here.

It depends on the intelligence of the listener, low levels are unable to believe.

It does not follow that someone is unable to believe because they have low levels of intelligence.

Challenge question : How do low levels of intelligence make holding beliefs impossible?

I will be silent forever so you could take your time preaching about what science is.

It does not follow that for someone to take their time to preach about science it is necessary for others to be silent forever (just for the time they are preaching).

Challenge question: What would be the point of staying quiet after the 'preaching' had finished?

Mr.B spoke some opinions about the difference between science and religion but this instead caused Mr.A to attack Mr.B that Mr.B never accepts anyone's opinion. 

It does not follow that because someone speaks opinions they never accept anyone else's.

Challenge question: How could they possibly know whether Mr.B ever accepts anyone's opinion?

B is on the right track but lost focus. The statement “What do you have to prove that your religion is scientific, unlike the other religions?” goes too far. It should stop before the last phrase and read: What do you have to prove that your religion is scientific?”

When A responds: “It depends  on the intelligence level of the listener, low levels are unable to believe,” the B should say, “That may be true, but what evidence do you have?”

Without the presentation of credible evidence, there is no reason to accept the proposition, which I tacitly understand to be A’s religion is scientific. 

1. Question: What do you have to prove that your religion is scientific?
   Answer: It depends on the intelligence level of the listener.
   Comment: Any evidence someone has, are not dependent on the intelligence level of the listener. Only      the level of understanding the validity of the evidence is dependent on the intelligence or the experience  or knowledge of the listener.
2. Claim: Low (intelligence) levels are unable to believe.
   Comment: People with low intelligence levels are not unable to believe but may be unable to understand and evaluate the evidence. Belief though, has nothing to do with evidence or proof.
3. "Mr.B told Mr.A that he committed the Ad Hominem fallacy" Actually Mr. A just avoided to answer the question by introducing another claim that "low levels are unable to believe" probably as a red herring . I don't see any Ad Hominem fallacy.
4. As for Mr.A response "Ok, I will be silent forever so you could take your time preaching about what science is" I can't say I see much connection to the previous dialogue. He's just playing the victim card implying that Mr.B forces him to be silent. That's an implicit and unsupported accusation that Mr.B's purpose is to keep Mr.A silent. Another attempt for red herringI guess. 
5. "Mr.B spoke some opinions about the difference between science and religion but this instead caused Mr.A to attack Mr.B that Mr.B never accepts anyone's opinion."
   The "never accepts anyone's opinion" implies that Mr.B disagrees not because Mr.A is wrong but because Mr.B wants to disagree with people, which is the psychogenetic fallacy and it is also amazing familiarity because no one could know whether Mr.B disagree with everybody unless that conclusion is deduced only from the interactions with Mr.A, which in that case it is hasty generalization .