Renovation supplement?!?

Hello together, strange case with me … maybe even just an abzock attempt of my insurance representative? I am fully cascade insured with my car and the annual premium was so about 900 EUR a year (seasonal license plate). In autumn I then had a basically smaller accident, in which I slipped off the road and got a wild fence with the whole right side. In this case some sheet metal work, new rims and a complete paint, which caused a BMW N The insurance rate rose by the downgrading to about EUR 1250 and was already paid by me in March, as the season registration mark began again with April. Now my insurance representative calls me today, that the headquarters wanted to cancel my insurance, but he could convince you, that the insurance company would be able to cancel the insurance. In addition, the insurance exists again in addition to the premium adjustment by the downgrading to an extra “recovery surcharge” of 20%. Incidentally, this is not a low-cost provider but one of the large well-known insurance companies. Does it seem to me to be very strange. Is this really acceptable or common practice? Can an insurance just add 20% in addition to the downgrading due to the damage case? n? Merci & Best regards, Joe