Planet Fitness

So I went to Planet Fitness in Buffalo, NY to get my 13 year old son a membership. They were very nice and guided me through the sign up process. My son got the black card and went on to exercise with his friend as a guest. The next day I dropped them outside and they went in, I get a call from them two minutes later. The manager kicked them out and told them they are too young to be there. He even told them he is going to cancel their membership because they are too young to even have one. The should be at least 16 years old.
My complaint is, Why was I allowed to sign them up in the first place? According to their website, 13 is the minimum age to get a membership. When I called and asked them the manager literally yelled on the phone because he didn't know why they were even given the membership. He had no clue about the age on the website and kept arguing its 16. then he hung up on me. I called back the lady who picked up said, they can come but I have to sign some waiver which I wasn't told the day I signed them up. Then she was like but the membership is cancelled, though it still shows active on my phone. Basically all the employees were not on the same page. The worst manager and employees on the PLANET!