I resubscribed to Fios a little over a month ago. I wanted to rent the router rather than buy it, but I was charged a $50 installment payment on my first bill anyway. I called and asked to have my account changed from purchased to rented router, I was told that this was done and I would see a credit on my next bill. I just got my second bill and there's no credit and I am being charged another $50 installment. 
Is there any chance of getting this changed or should I just consider myself lucky they haven't screwed it up worse than that?