friend backing out of verbal agreement need help fast

Illinois-This guy assaulted my husband at our house, during which my hubby's glasses came off (3 months old worth $450). Guy finally admitted 2 weeks later he took them and threw them. Police were then called, cop said he would press charges on both for assault since we took so long to report. Well, we didn't have proof until then he took the glasses. The guy told the cop his wife and I made an agreement for her to pay me $500 (he doesn't have a reportable job). 3 days before that incident, we gave these people $50 for their old washing machine, which since the assault we didn't receive. The attacker's wife physically took the cash for the washer. She called me on the phone and agreed to pay $50/month for 10 months. I said I would type a payment agreement for us all to sign. I emailed her asking when she could send first payment, since I know she only gets paid twice a month, she responded "maybe next month". I sent the paper adding a payment date that was 3 weeks later hoping this would give enough time for them to come up with the money, and now they refuse to sign.
So, will my verbal agreement with his wife hold up in small claims? I have sufficient proof through emails before they started blocking them. Do my husband and I sue them both jointly? Is she responsible to pay since she called and agreed to my payment plan? I'm sure she is at least responsible for the washer money, can we sue them at the same time for these two incidents? I feel the issue is my agreement with the wife since her husband passed the buck to her.

That agreement will hold up in small claims.

It is separate from all your other police issues, and binding.