Got the sim but never ported. Now on temperorary number

Hi everyone, I was thinking of porting my Fido number to Chatr for which I bought a new sim and bought a plan and sent "yes" on the sms received. But after 30 minutes, Fido called me and gave me much cheaper plan than Chatr. So I decided to stay with Fido. Now, I have temporarary number of Chatr. How to cancel it & take my prorated money back ?