Renewed my contract for 'free' but then charged erroneous fee!

I have been a good Fido customer for many years and after receiving letters encouraging me to renew my contract, I decided to do so on June 25th. After all, I had plenty of Fido Dollars accumulated to use towards a new phone. I placed the order/renewal over the phone for a new Motorola U9 and was told it would arrive within about a week. I phoned back the following week to check the progress and was told the phone is (and was) never in stock. They cancelled my order and told me to go to my local Fido store. After some delay at the Fido store (the computer locked my FidoDollars) I was finally able to purchase a new U9 and renew my contract. I thought everything was good.
Then I get an extra charge for "Fido Dollars" ($56) on my next bill. I called customer support to point out the error and they said they'd take care of the error and I could just pay my regular bill amount. However, the error was still there when my August bill came (plus a late fee). I called customer support again and was told it would be taken care of. Many broken promises and no resolutions as of yet (plus another late fee for September). It's very frustrating. I always pay my bill on time but I refuse to pay for their billing mistake. I've never had any problems with Fido until now. I didn't even know one could be charged for "Fido Dollars"...it's something you earn and use, like Airmiles, isn't it?
I wonder if other customers have gone thru a similar situation. Please someone help me resolve this situation or point me in the right direction as to who I can contact to fix this.
Thanks