Not getting refunded for overpaid phone bills

Got $35 deal on Internet and a free unlimited phone line in September and like many others, I got $ 69 bill in October on my phone line. Called customer service, I got informed that I have to pay for the first month and the rest of the 12 months are free (I WAS NEVER BEING TOLD WHEN I GOT THE DEAL). ok fine, they credited me 20 dollars on the bill so I still ended up paying $49. Then in November, I got a bill of $40 dollars for the phone line AGAIN. I went in store, the sales credited my account 40 dollars and requested for refund on the October payment but somehow the 40 dollars credit did not apply, my credit card still got charged and never got my October amount back. I went back in store in early December after I got charged, the sales requested for refund for both of the October and November and told me I should receive the refund within 2-3 days. Fast forward to today, I have not received any of the REFUNDS. It is so frustrating as I'm paying for the miscommunications between the Xfinity department and poor system. I have to spend all these time and effort by going to the store and try to fight with agents online and over the phone to resolve the issue while nothing is really resolved on the Xfinity end since all they do is just kicking the ball around.