i have purchased iphone4s locked to bell but but my provader is fido.Can i unlock this phone?

Ask Bell if they'll unlock it.

(82121)

Bell does not offer unlocking for iPhones. Sell it and buy a phone you can use with Fido.

No, only the carrier it is locked to can unlock it...but if you had a different carrier, why buy that iPhone in the first place? Sell it and get the iPhone for your carrier.