Security Deposit Return Question

[Douglas Underwood]

I just finished a 12 month lease with a bf/gf couple that were very nasty and abusive tenants to me (texts and emails). They were constantly complaining and picking fights with me. They just moved out and I mailed them a check for the full amount of the security deposit but only put one name on the check. Now they are complaining and threatening to sue me because I didn’t put both of their names on the check...even though they live together and got a full refund. Do I have to send them another check or can I finally ignore them and be done with them forever??