Incorrect billing

I spent HOURS yesterday, supposedly to correct this issue. Not to mention there is NOT a $128 credit as I was told yesterday; nor have the billing errors been changed, or a refund issued for the almost 6 months I've been being charged for devices improperly. Apparently ALL bc I began the upgrade online, my 1 kid wanted a different model and it was concluded in store. Ironically, we only did this to finish IN STORE, because that WAS supposed to prevent the EXACT issue that I’m still trying to fix, 6 months later… As well as after $788.22 of overcharges… I’ll be lucky to recoup my losses I’m sure; but it’s a real shame that the average consumer isn’t able to insist on repayment of due money with current interest rates applied; like any regular consumer would wind up responsible for. 
I only even had one of the several “representatives” actually even help me by confirming what even caused the account to never have been synced, so the ‘deal’ I was agreeing to, never even stayed on the account. Somehow, because of the 1 phone getting processed ‘In-store’ that’s why none of the device chat have been accurate. They were treated like routine, phones with balances that got upgraded. When none of my devices had an outstanding balance, in fact, three of them were already owned phones, that I transferred over! 
Plus I’ve been a customer of Comcast, technically since I was a kid, so add 18-19 years; but I’ve been a customer myself since 1999…. So if I have billing issues; I’d hazard to say, anyone else, should expect them.