In December my partners ex asked him if she could buy something off me - I run my own business. She lives close by but we, his ex wife and I don't have contact. Partner dropped it off but she wasn't in so didn't collect any money. Not a problem as I put in one of my standard invoices with many payment options and thought she'd pay up at a later date. Maybe give it to the teenager when we she comes to us for her week here (we do 50/50). Seven weeks has passed by and nothing. I did run into her in the town 3 weeks ago and passed the time of day, briefly, and she did mention that she was aware she hadn't paid me yet, but still no payment. My partner wants to send her a message to remind her (I don't have any contact details for her) but I don't really want him to get involved as the agreement was between me and his ex. I'm minded to just forget about it. Life's too short and all that but my partner thinks that's wrong. What would you do?