Cellc not doing the job

Everytime I send my phone in for repairs they claim it is blacklisted . Resolved the issue in Feb 2020. Took my phone in June 2020 again they said. It's blacklisted had to wait 3months to get my phone. Received phone only August or sept not sure. 2021 August took my phone in again they have issue clearly not doing their job . Tellih to resolve call centre not their prob . Se story with repair no one wants to take responsibility who is in charge cellc ?? You are on your own I wouldn't recommend cellc please rather Telkom or MTN not cellc people you'll struggle