It sounds like you have given a good effort to resolve your problems with no beneficial help from the lender.
As I see it, you next step might be to contact a good real estate attorney to represent you. The fact of the matter is that the common guy doesn't get the respect they deserve. Attorneys on the other hand, tend to get their attention. What it will cost for legal support might be well worth the investment.
Of course, it is always wise to check with your attorney as laws may vary from state to state. In Florida, for example, a valid reason for termination would be if it were evident that the agency had abandoned your property in that there was no interaction or any evidence of their living up to their contractural obligations in marketing your property.... more