Another ? Re What to do

I cancelled my bank account but before it was closed all the way (waiting for a couple of outstanding items), One Click Cash sent a dummy check through. I had a loan with them for $350 and the fee was $105. I already had sent them a certified letter telling them to stop all attempts at ACH, paper check conversion, calling references, etc. I stated the laws of Delaware and asked to be marked paid in full or at least work a payment arrangement for the remaining principle of the loan (seeing how they are not licensed in DE). I got an email from them prior to them receiving my letter stating I was past due for $560. I then sent a certified letter requesting a verification of debt since I could not understand where they were coming up with this total due. I have gotten confirmation of the reciving of both letters by the USPS. Then yesterday the check went through my bank for $560. Should I contest this check with my bank showing them copies of the certified letters I sent. I am not saying that I don't owe them money but I don't owe them $560.