Refund not paid since October 2018

I submitted my tax return in October 2019 with changes in banking details. I was required to verify my banking details which I also did and completed in October 2018. However, my refund has not been paid to date. I have been calling every week and I have been told by the consultants that this has been forwarded to their team leaders which will invistigate and contact me with feedback. I haven't received any feedback on this, not even one team leader has contacted me. This is really frustrating because I haven't been told what the issue is and the documents I submitted can be seen on the system.