Insurance problems

Hello together. I have a little problem with my car, and the corresponding insurance. It’s like this: My car insurance (partial kasko) was completed by my girlfriend’s grandpa (because of the amount of insurance contributions), I was only registered as a driver, and therefore didn’t have to sign anything. Now the monthly insurance fee was always debited from my mother-in-law’s account (or we should say better be debited). After a while, a letter comes from the insurance company, which could not be debited from my mother-in-law’s account, and therefore my car is behind. Now, my girlfriend’s grandpa wants to ask me to the cash register, and how did he say: “Get the money in another way” almost ads me. If I think about it that way, he can’t do it at all, because I didn’t sign anything with the insurance company or ? I wanted his A nzeige come before, and show my mother-in-law. Can I be somehow prosecuted there? Liene Greetings masterriemi1702