If I send a creditor a letter, trying to make payment arrangements to repay my debt. Following that letter I sent the amount that I informed them I could afford to pay and they cashed the check. Am I wrong to assume that they were agreeing to the payment arrangement? I just feel if they didn't agree then they wouldn't have cashed that check. Instead they filed for garnishment of wages and my savings/checking joint accounts, now my family is suffering, because we can't pay the rent, insurance, buy groceries, until they release the accounts.
I am not licensed in your state but I can offer some general advice.
If you sent the check to the regular payment address and not to the corporate address then there is no legal affect to them cashing the check.
Also, you would have had to send the check, with the letter, and perhaps even indicating on the check itself that cashing the check will be considered acceptance of the offer.
You should contact a local attorney to talk about your situation.