Hi, I received a negative balance on the final bill
Do I have to do anything? just waiting for a refund or cheque by mail?
but I moved out of the previous home.. so can I get a refund or cheque by mail on a new address?
The negative balance means Fido owes you money and they will send you a cheque by mail to the address on file, if you are no longer at that address you will have to reach out to customer service to have them send the cheque to the new address.
You can contact them through any of the available methods listed here.