Unhappy service

Europcar is a bad company and poor service I rented a car i got accident they said I have to pay another security to get another car . Which i did and the second car we didn't do any inspection because it was late . After they told me that they don't have insurance for their cars I have to pay while my security i pay for second car they didn't pay back . They are harassing me to pay them R6310.55 .I don't understand you rent out a car and customer pay security for accident and theft after you can said you don't have insurance for the car .