As of the 1st of August, payment histories on your cell phone account now show on your credit report right next to credit card and loan payment histories.
For some younger borrowers, this could turn out to be a positive development, as it will give them another source of reportable credit history when applying for car loans or mortgages. However, for others it could be a negative. As have many other Canadians, I have personally signed for a cell phone bill for one of my teenagers, who is theoretically supposed to pay the bill himself each month. Am I going to chance him messing up my credit history by missing a payment? Not even close. To err on the side of caution, I have actually overpaid his bill by several hundred dollars just to make sure there always is a credit on the account.
So next time you are pissed off at Bell, Rogers, Telus or whomever you deal with over some seemingly random charge on your bill, my best advice would be to pay the bill first and fight for a credit after the fact.