You can put the account on seasonal hold for 6 months maximum which costs $15/month if your coming back in that time. If not then you'll have to cancel and pay your final bill including usage and amount owing on your tab. Either way you will have to call Koodo to have your account t put on seasonal hold for up to 6 months or to cancel.
You will lose your plan and have to choose an in market plan at the time you reinstate your account after seasonal hold. To take off seasonal hold just go into self serve and choose the new plan.