Debited my account on incorrect dates

Can first for woman please stop harrassing me with sms's and letters saying I did not pay ny policy. They are trying to debit my account whenever they want. My first premiun was 26 October 2019, the next was supposed to be 26 November and so forth. But in November they sent me 4 emails, texts and even called before the 26th saying my debit order is rejecting. Then they debited my account on the 21st and 29th November then today again the 3rd of December they debited my account. After their debit on the 29th I reversed the 21st debit order. I'm going to reverse today's debit order. PLEASE debit my account on the agreed date 26th monthly or I'll find another insurer. Reversing this debit orders creates a bad credit rating for me and I don't want to do it anymore.