Where has my investment gone?

I invested quite a large sum of money in the Bidvest Fixed deposit in 2017. After a year, I received an option letter: cash in, or re invest. I completed the reinvest option for a further year. A year later, 2019, I expect to receive another option letter. This does not arrive. I queried this with the bank, providing confirmation proof of sending the 2018 letter, and receiving the confirmation of the reinvestment until 2019. I was told that they could not find that account, and that the query would be 'escalated'

A month on, and no further information received, despite emails, and phone calls. I simply cannot get to talk to anyone who can tell me where my funds are. Everything just goes quiet.

I want to know how such an investment can be so poorly handled by a responsible bank. Also, do they not care for their clients?