Removal of account

Afternoon I had a contract with mtn 4 years ago which was sent to legal and now that R5689 that was overdue is still showing on my credit report and it's currently prescribed and I've sent numerous emails for them to remove it but no luck I can't call them because I'm using vodacom now and my emails never get returned

Contract in question *** ID ***

Please Help me remove this old prescribed account which hasn't received a payment nor arrangement in over 3 years but mtn legal still has audacity to keep the record that contract was closed and my account with mtn closed aswell

My Contacts *** ***