Hello Caskie_9,
Welcome to the community!
No, Fido will not blacklist devices due to non-payment. Only a customer can request an IMEI to be blacklisted. If an account has defaulted, all costs are charged to the account (including the cost of phone). If the payments remain unpaid, the account would go into collections (see here).
You should note that the last user has 60 days after their last usage to blacklist the phone. The seller may blacklist it within the first 60 days to prevent any usage on the device, but after 60 days this cannot be done. Though once used on your account, you may blacklist the IMEI at any time as well. Therefore there is an uncertain period of 60 days if you choose to make a private purchase (taken from link above).
If the phone is indeed in working condition, you would need to contact the seller to ensure they did not blacklist the device. If the seller sold the device on behalf of someone else, you would need to contact that third party.
While Fido won't blacklist a device for non-payment, they may suspend your services. If you're having difficulties paying for your services, you might consider contacting the credit operations team to make a payment arrangement.
Hope this helps 😀
Cheers
