Revoke/announce residual liability insurance? (Commerz Finanz)

Hello I’m new here and have a few questions at once. I bought a new car last week. About half of the purchase price is financed by Commerz Finanz. The dealer said that it comes out the same with the financing, whether I take the RSV with me or not. I now have favorable interest rates. If I had omitted the RSV, the interest would have risen, so that I would have come to the end almost the same amount. Sound plausible first. For this RSV I pay approx. €550, which were included in the financing (at 1.99%). Questions that appeared afterwards:1. Can I cancel this residual debt insurance directly at the bank in writing?2. If so, is this reasonable in retrospect? Or do I run the risk that something will change in the financing afterwards (higher interest rates etc.) and I may even be worse?3. In the case that I pay a higher closing rate and trigger the loan, I would get about €550, which was included in the financing. probably a part of the RSV refunded? Or is there no possibility? Dear greetings, Sabse