Insurance

Not sure where to post this so sorry if I put it in the wrong spot! Took our son to his first dentist appt (my old dentist when I was a kid- still remembered me), and they said our insurance was inactive so we had to pay the $55. My hub got it all straightened out and our insurance paid the dentist too. So I called the dentist to make sure that everything was ok- and she said that once all the paperwork was in order we'd get a check in the mail for out $55. We'll, that was at the end of December and still no check. I'm not a confrontational person and I don't want to seem desperate for the check - but 55 bucks is 55 bucks. Since I knew the dentist from when I was a kid I'm more hesitant to call. Also, I trust him bc he specializes in kids dentistry. What do you think I should do?