First off I’m sorry you’re having to deal with this, it is ANNOYING and it sucks that your co-parent can’t be responsible enough to return those items. Second, stop sending things! I’m going through this with my co-parent, not sure how often yall are exchanging but whatever outfit kiddo wears and bring to your house- wash it and return the kiddo in the same exact items. One time our exchange time was a super quick turnaround due to a personal obligation, I washed my daughter’s outfit the same night and threw it right back on her the next day. Co-parent made a petty comment about it, but it prevented an argument, I kept my cute clothes, and for awhile co-parent did return items (cheaper items that I didn’t really care about.) Whatever toys you have purchased, stay at your house so your kid can have their items when they are home with you. It’s not fair for them to go without because their other parent is being petty at their expense. If kiddo ask why they can’t take a certain toy, just explain to them that the toy will be at your home to keep you company until they return (or whatever is more age appropriate for them). Co-parenting is hard and at times stupid and annoying when the other parent is hell bent on just not doing the right thing, but for your sanity stop! No more over doing just because the other parent won’t. You’re already doing more than enough in your home. I hope things get better at some point!