Fido add-ons are a rip off, and are bugged.

[dswd]

I purchased an add-on data plan for my tablet only plan. It was working well until I tried to cancel the add on. I utilized the text-triggered cancellation request, but the system refused to accept my add-on cancel code. I phoned support, and all they offered me was a ten dollar credit even though I have clear proof that I canceled the add-on.
Thanks for ripping me off Fido. You've lost a customer.

[FidoCharles]

Hey @dswd , welcome to the Community! 

It's definitely not the experience we want you to have with our add-ons. What happened exactly when you tried to remove it by text? What message did you received by the system?

Was it during a new cycle?

Note that when you request a Monthly Data Add-on to be removed, The changes take effect on the first day of the next billing cycle, so the charges for the current cycle are still applied. You can still use the data from the Add-on you just cancelled during your current billing cycle.