Questions regarding contractual agreements are a matter of law. As such, real estate agents cannot give an opinion of a specific nature. Agent opinions can not be used as a basis of terminating a contractual agreement between parties. Contractual interpretations are a matters to be handled by attorneys.
My recommendation is, first, visit with the real estate agent with whom you are working. If that does not lead to a resolution, visit with the agent's manager or broker.
I'm not sure about your question. If you signed papers with an agent on one home. I would think you will have to see this transaction through. If you go with another agent in buying that same house you may owe a double commission. If your commitment is only for that one house, you should be free to work with another agent in looking for a different house.
Regarding your question on the bank negotiations, remember in real estate (Statute of Frauds) no terms are binding and enforceable unless it is in writing.
Good luck on your home buying.