Private used car sales buyer claims defects one day after!

Hello all, I have a huge problem: I sold my Honda yesterday, as far as so good. Sales price 1550,- In the contract I “sold as seen” and excluded the withdrawal. Now one day later the seller arrives and sends me pictures of allegedly defective brake parts and a supposedly broken and welded front axle. This should come from a concealed accident. Lt his data total damage! After yesterday, today the brake is supposed to be fixed. By the way, I drove 2 weeks ago 900 km with the car in 2 days. There happened nothing more funny. I announced defects such as the rear crash and recorded them in writing. Brakes in front were renewed, so a rear renewal was excluded. He now refers to a cost contribution or he invoices me these costs + some towing fees, because the train allegedly is no longer suitable for traffic (tüv without having to make brakes at the front in the near future in July NEW) And brakes at the front have I renewed. What do I do now? Is this a fraud? He buys a similar car, he sold his previous one to have 10 Ps more?! Should I ignore this and let it happen to a possible litigation? That’s not so kosher. I hope I get quick advice here!