Change of insurance and cover card

Hello experts, I have quit my old car insurance on 31.12.. Since 1.1. I am with another car insurance. (=change of insurance) Now I received a “bad” letter from the registration office. The (old) insurance has announced that the insurance cover ends on 31.12..12.. Since I am not insured, they give me 3 days time to hand over the signs OR to submit a cover card. Otherwise, costs up to 1500,- € and decommissioning of the vehicle… I fell out of all I had never taken care of a cover card, because I only change the insurance. (covering cards, I thought, you only need for a registration/re-registration) The new insurance company then, on my initiative, sent a cover card to the registration office. Then the procedure was stopped. I received an invoice of 45,- Euro from the registration office, which I should pay now – together with the indication that I could pay the Ask: Am I responsible for presenting the cover card to the admission authority (uncertainty does not protect against punishment) OR should the new insurance have independently informed the admission authority??? Greetings Fan.