Won't accept payment and garnished bank account

by Linda
(Pueblo, CO)

After paying on a debt for 10 months, I was two months behind (the final two payments). I contacted the collection law firm and let them know. They said to pay it within 30 days (I only get paid once per month) and since it was the last payment it would be fine. I did pay them and then I received the check (uncashed) back with a letter stating they couldn't accept my payment (no reason given). Then, they must have wrote down my checking account number off of that check because the next thing I know my bank account is overdrawn. I DID NOT receive a notice to be heard in Court from the law firm or my bank. My bank sent me a letter dated one day AFTER the garnishment. Also, they drained the joint account I had there with my Dad. I have two questions: 1) Can they legally write down my checking account info? Isn't that protected financial information? 2) Can they take funds from a joint checking account that is NOT subject to "community property" standards like a husband/wife account?