You should use your credit card exclusively and pay it off every month and build up your credit history. Only having a credit card for two months you essentially don’t have any payment history.
Koodo has some good prepaid plans as well as Telus. You have to start somewhere, before going post paid.
Paying off your credit card every two weeks suggests you are making payments with every paycheque. It might build your credit faster to pay monthly shortly before the due date. While keeping your credit balance low by paying with each pay period keeps you comfortable with the balance, paying according to the terms is likely what the algorithm is looking for (ie. paid in full by the due date).
Also, as @WestCoasterBC indicates, put all your regular purchases on the card (gas, groceries, incidentals) to build your credit faster.
Do you already have a Telus plan? If not, it may make sense to buy the phone outright, or keep your current phon e as a BYOD, and just get a plan meeting your needs. Once Telus has a record of your payment history, they are more likely to advance you credit.