Debited One Month Earlier NOW WHAT?!

I signed up for this insurance as I thought it was the right thing to do. Even though I had a niggly feeling that maybe I should not go with them. Sent through all the paperwork and that was it. Towards the end of the month I called them to ask if I could have my account activated the 1st April and that I would only want my first deduction to be from then and I received email confirmation that it would be April 2020. I then also phoned,as my phone records every call I make, so i could have some proof and they also assured me on the phone that the inception date was definitly the 1st April. Lo and behold I wake up this morning and my money has been taken???!!! Now how does this happen when I clearly stated,over the phone and via email that I specifically wanted April? Is this not theft? I have written proof that they confirmed April and voice recordings say April? So now what? I will also now not be able to afford other things this month as I clearly told them in the call that if they took the money from me this month I would be in trouble. Thank you AGS for doing this to me... I will rather cancel my "insurance" effective immediately and i want my money back ASAP. Otherwise I will take this matter further because from my point of view this is theft. I never gave permission for March! ONLY APRIL. Rectify immediately. I AM VERY UPSET!