Just debited my account with a fine handling fee with no proof

Three months after returning my hire car, I got a call from my bank that I had exceeded my overdraft facility. After checking my account, I found that Hertz had helped themselves to 5 x R295. Upon approaching them, they said it is a fee for handling fines. I explained that I had not heard of any fines and where are the fines, please send it through to me. They responded saying they can only send it to me after lockdown. I said that is fine but then reverse the charges until such time as they can provide me with proof. Well since then, it has been absolute silence. So now, during this very stressful time, they have affected my credit rating, taken my overdraft over its limit and no-one is responding to me. I have 4 to 5 emails without a single response. I have other issues but I am not going to get into those.