Charged for an unused Netflix account

I was billed for 5 months of Netflix because it must have accidentally created a new account on my Flex box when I made a mistake logging in. When I realized it I had to call Comcast multiple times to get them to stop charging me the monthly Netflix fee, but the damage was already done by the time it "cancelled."  Now nobody can help me resolve the refund for the money that was taken, because Comcast keeps telling me that it's a "third party" app and they don't deal with this issue. But when I contact Netflix they have no record of any account, because I never made an account with them, it's all attached to my Comcast box and account.

This is a Comcast problem and I've probably called up to 10 times for hours each time trying to get this resolved and it never happens. I don't understand how the customer service is this terrible and every time I try to get this escalated to speak to a manager, they say they will not do it. So I just keep running around in the same circle with the same problem. On top of that Comcast decided to increase their regular service fees so I'm being charged double for the same level of service as about a year ago. Comcast pulled the funds, so even if the money got sent to Netflix eventually, they should be able to work with me and Netflix to resolve this issue of paying for an unused account.