Invalid account reflecting on ITC

I have paid off my accounts with African bank in September and they also sent me paid off letters but when I check my report with TransUnion one account is still not closed due to the invalid account that's reflecting on their system African bank instead of writing full account they wrote the last 6 digits of the account and TransUnion was unable to clear that,I have called African bank so many times addressing the issue even sending emails to them addressing the issue till today the issue hasn't been resolved now I escalate the issue to the management to assist because I really don't know what to do.

They can reach on my mobile