We have been dealing with this awful woman for months now, with threats of garnishment, imprisonment, and generally nasty insults. After a call this morning, we decided to just use our income tax check to pay off the debt completely. However, when we told her that would be sending her a post dated check for 30 days from today's date for the entire amount, rather than a partial payment for today's date, she refused the payment altogether and began to threaten some more. If I send the payment in full anyway, will they still refuse it and send it back? And if they do send it back, what can I do from there to avoid being prosecuted?

First off, you can't go to jail for not paying a bill.

Second, why are you bothering to send her a post dated cheque? Why not just wait until you have the money and then send it.

I am under the impression that the US Banks will cash cheques at any times, whether they are post dated. I need someone else to clariffy that point for me though.

Either way, don't send the cheque until you have the money to send.

Just ignore her.

Let me stress. You can NOT go to jail over this.

Post dated checks do not have to be accepted. Many places take them but other places will not. In some states they are not considered legal

Next of course you should not even be talking to them on the phone, never, never did I say never. Next of course you can't go to jail, this is a lie and if they are nasty, then they are not a company I would want to do business with. I would rather call the orgnial lender and pay them ( that way the collection firm won't get any money from the deal.

Next I would tell them to... ( then go to confession of course) and not pay them anything till the check comes in and I can pay them in full without it being post dated, ( what if the income tax does not come back in 30 days)

What is the worst they can do, file a legal action against you to try and get a judgement and then a garnishment ( I doubt they could do it in 30 days)
I would refuse to accept any calls form them and make them only communicate with you in letters. You will see that there is no threats and that they will accept all sorts of payments that way.

And once I had the full amount in my pocket I would not give it to them then either. I would offer than 1/2 and no more than 3/4 to settle the account in full. ( or I would go to the original lender and offer them that, since they are losing at least 1/4 to 1/2 to the collect agency anyway.)

If you send a post dated check, or they "change the date" they could run it though, if the bank don't catch the date it will come back
With bank charges and then they will threaten you for real with criminal charges of a bad check plus add all sorts of extra charges.

If you send payment for an account and they refuse, they have dishonor the account. Put them on notice of the dishonor, this will cause any problem for them if they take you to court. By you tender of payment you are in a position of honor. All this can be found under the UCC.