Cannot say why account is blocked

We have been trying for more than a week to send a parcel on our account. We have been told our account is blocked and nobody can access any record to tell us why. Fedex has recently taken over TNT, which has caused so many issues. There is no way to contact the accounts department, as apparently they are working from home and can only be reached by email. These emails never gets responded to. I have been able to get the name of our credit controller, Sandra Govender, who is also not responding.