Bad service

I have rented a car from 15 October 2021 to 18 October 2021 at Cape Town International Airport. I have filled the motor car's fuel tank completely and returned it's in a original state. They have withdrew an amount from my credit card but I'm still waiting for an invoice, after I queried them twice on their website and still waiting for an answer! There was no such problems all the years I have used them. This is very unprofessional and I will never rent a car from them again!