Concluding and billing accordingly of the rental taking forever

Good afternoon I rented a car with Bidvest at ctn international from 31 aug to 5 Oct up until now the rental has not been finalised and billed accordingly so my dep can be refunded I was told Deidre is working on it when I phone she is forever not available. I contacted the customer care via email no response and I called today spoke to Amanda Rose who said she will come back I am still awaiting, Can I please have this query sorted out immediately its exhausting. I will never ever rent a car from them very disappointed to say the least.