billing issues

My Dad went to the Xfinity store in Southwest Plaza in Littleton, CO on April 9, 2026.  He went in for a new remote.  Somehow he ended up with a new Samsung Galaxy Tab A11+ 5G tablet, that he said he didn't want, but the store employee insisted that he needed to take it and that it was free. The employee also seemed to imply that by taking the tablet, his cable bill would be credited $60 a month. He told me what had happened, and I recommended he return the tablet that day.  He went back to the store that same day, and they refused to take it back. Now he is getting multiple charges for the tablet on his mobile Xfinity bill.  There is a $10 charge listed under the account level charges category, and a $7.77 charge listed under the New category (there is also a 3.89 credit under this category).  There is a separate charge on their credit card bill for Xfinity mobile for $23.49 that we are assuming is also related to the tablet.  Also his mobile phone bill has always been around $67-75 a month.  The bill that will be automatically charged to his credit card on June 6, 2026 is $161.60.  He is being charged for a data overage of 4 GB.  His phone usage has not changed, so we are confused as to why he is using so much more data. We would like to return the tablet and be credited for the aforementioned charges.  We would also appreciate clarification as to why the data usage has changed so dramatically on his phone. Thank you.