Unhappy about naked insurance

I'm a current unhappy client for naked insurance, they canceled my insurance because i had failed for paying the monthly premium for April and may, I rejoin 26th of Nov 2019 they quoted me an 148 for pro-rata period and then boom 1048 went off, no problem thought it's for the month of Dec the 1st of December 745 debit order again they say it's for Dec, I asked what was 1048 for they say for May and April when they canceled my account had a balance, I am totally ****ed with this, firstly they didn't tell me I had to pay the balance, according to my understanding for insurance no payment no cover why should I be billed for the past months it's six months back for goodness sake, secondly they didn't cover for anything and I did not claim why I had to pay R1800, It is really bad had I been told about the previous balance I wasn't going to join them