Mobile Account Problem

On Monday, we visited the local Xfinity store to replace my son's phone. The young woman who helped us indicated that with the upgrade of his phone, we were entitled to a free tablet. After checked again to make sure it was really free, we took the tablet. She worked on setting up his new phone which seemed to take a long time. After an hour we left with the new phone and tablet. Later that evening I checked my account and the new phone and tablet were listed along with three bring your own Iphones. And the tablet listed was not free but showed device payments. I made another appointment for the next day and went back. A different young lady helped me but did nothing but give me a long explanation of why the phones were added which made no sense. She made an appointment for me for the next day with the same young woman who first helped us. That evening I get an email from Xfinity that I am over my data plan. I have the 1gb plan and my son is on unlimited. I don't use my phone that much so it made no sense. I check my billing and instead of the $54 I usually pay, my bill is now $120. And one of the bring your own phones is the culprit. So Wednesday I am back again and another long explanation of why and supposedly the phones have been removed and the adjustment for the free tablet will show. I just checked my account again and the phones are still there using my 1gb service. Apparently the folks int he store cannot get it done. I DID NOT ADD THE 3 BRING YOUR OWN PHONES TO MY ACCOUNT. Can anyone hep clear this up.