Unable to upgrade with Cellc because of Debt Review

My contract is up for a renewal however Cellc states that i cannot upgrade due to being on debt review...How was i upgrading all this time? I have been with Cellc for the past 5 years now so basically i need to cancel my contract and go to another provider that can assist me. Why now all of a sudden you declining because of debt review...my contract with Cellc is not on debt review so how does that affect the contract? all my payments have been successful to you guys since the start of my contract... I would appreciate if someone could call me with an explanation.