Automatic tip added to birthday party venue without permission

I held a birthday party for my son a few days ago at a gym type venue. We were promised a party “host” and that setup of decor would be included in our cost. Not only did we not have a host we only had access to the party room half an hour before the party ended because there were overlapping birthday parties that day (which we were also not told about). We were unable to set up any decor as we had to rush pizza and cake and the host was nowhere to be found during this time. Despite all this, I saw an extra 50 dollars charged on my credit card a couple days later. When I called they said it was a ten percent tip which I had no notice of or even signed off on. Thankfully they took it off but I’m angered at the entitlement for thinking a tip is mandatory for subpar service.