UBER IS HOPELESS

I set up an account with UBER a long time ago but did not load a payment method. Earlier this month in LONDON I tried to put in a credit card which was set up for UK and had a credit limit of R100 000. UBER mucked me about for days ultimately telling me to go away. I wrote to them but no response other than to say I had been blocked. I still am. My credit record is better than excellent but they tell me my credit card is invalid, despite the R100 000 limit (unutilised)