500€ Contractual penalty wg. Km-exceeding just?!

Hello, after a TK-damage (in which the car was examined by my VU) received a letter that I exceeded the specified KM-performance and therefore should pay a penalty i.H.v. 500€! How does this amount justify itself?! Especially since the damage now occurred is not related to the running performance, since it is a theft damage! And how can I know beforehand what I will drive?! is like clairvoyance. Had with contract closing the 10TKM was specified, but then due to unforeseeable circumstances (if the car had to travel across Europe) a running performance of around 30TKM was achieved. I never got a questionnaire on current information! Ok, I know there are contracts where I have to specify this by myself, but WHEN? with the day I exceeded the running performance by 1km? Contract was concluded last year in May: have now in 1 year and almost 2 months 30TKM instead of 10TKM acc eight. Who says the insurance company, that I did not actually drive only 10TKM last year and the 20TKM only in this year? is there an opportunity to resist this? Thank you and greeting Martin