Lied to about service and now no one is calling back

I switched over to AT&T in August of 2019 from Sprint where I had been a customer for almost 17 years.  The ONLY reason I switched to AT&T was because the store was running a Buy 1/Get 1 promotion on select Iphones AND they were able to support a comparable plan as I had with Sprint.  I was told by the store rep that my total bill before taxes and fees would be $113 and with taxes and fees it would be about $120.  Since that was comparable to what I was getting with Sprint and I could get a phone for my sister for free (she needed it for health related emergencies) I went ahead and signed up.  When I got my 1st bill  I wasn't surprised by the large amount due to the partial month charges etc.  However when I received my second bill I called the customer service line to inquire about why it was $146 and why it showed an installment price for the free phone. I was told by the phone rep that this was "just how the system worked and that I would be charged the $25 installment fee for three months but then would get a refund of $75 with my December bill and no additional charges after that.  He also confirmed that my regular bill would be $121.66 going forward and that this total included all taxes and fees. 

I received my December bill over the past weekend and not only didn't I receive the $75 credit I was promised, but I am still being charged for the FREE phone so I once again called customer service.  I was on the phone for over 3 hours as the reps tried to first tell me that there was no buy 1 get 1 free deal going (even though the store was covered in posters) and then proceeded to tell me that they found a promotion but the service I had didn't qualify for it (not what the in store rep or previous phone rep said) and that this was as low as they could get the bill.  The call was supposed to be escalated because amazingly ALL of the managers were in a meeting and that I would hear back from someone last night by 6pm EST at the latest.  Of course that never happened and AT&T LIED to me about service so I need to speak to a District or Regional Manager ASAP.  I will not stand for these lies meant to trick people into service and would have stayed with Sprint had I known this is how AT&T does business.