Sheriff threat

I have been getting calls regarding settling my account, unfortunately when they call I am in meetings during the day at work and don't have my phone with me. When I try to call back or respond to an SMS I don't get an answer as I am sent to an automated receiver and I wait for a long time to get assistance and my airtime finishes while waiting

Now I have been threatened by the sheriff but have tried to respond to them to no avail. This process is frustrating because even at a branch they cannot assist me