DS1 did a judo club at school. It requires a deposit for the kit. When we came to leave we returned it, washed etc and find they didn't return the deposit until we chased them up with a letter. / receipt
Now in secondary another club this time with a large deposit (around £100). When I returned the kit I was told most parents don't bother updating their back details to get the deposit back. This club is at a private school but we are not, they also take pupils from the state school nearby.
Anyway, I did then send an email to update them and again having a difficult time getting the deposit back! I wondered if others had found this also with clubs etc