Beauty Essentials Spa

I purchased a Groupon for this spa and called in late April or early May to schedule my appointment. They couldn't schedule me until early June, but that's happened to me before so I didn't think much of it. I had to reschedule that appointment, though, because I had to go out of town. When I called to reschedule, I was told in a somewhat curt manner that they normally have a 72 hour cancelation/rescheduling policy.
Fast forward to today when I went to my appointment. My session began with a, frankly, unnecessary tour of the facility. I'm just there to get a massage, so I really don't care what else you do in the other rooms. The massage itself was fine...I mean she did somewhat focus on the areas that I had specified needed some attention. My main problem, though, was being forced to tip 18 to 25%. Not only did the therapist pull out a calculator to check my original tip, she had LOCKED THE DOOR so that I couldn't leave the building! I gave her my original tip amount & went to open the door to leave but couldn't. I can't make this stuff up, y'all. She told me that they required a tip of 18-25%, and then said "that'd be about $20." I was so uncomfortable and unsure of what to do that I just handed her the rest of the cash in my wallet, which made my entire tip $20. When she was satisfied with the tip, she got up and unlocked the door. I couldn't get out of there fast enough.