Moped bought, much broken… Read!!

I bought a Aprilia RS 125 Bj 1999 with 24242 km according to Tacho So, times the cards on the table. I bought the thing at Ebay, did not see it before because it stood 450km away from me. Included were among other things New tires+New brakes+New fork bucket rings+New pistons+New clutch. The rear mature has run off, I told him, the Tachwoelle is torn, I told him, there he is with the price at 100Euro down. Since it was yesterday evening 21.30hr when we got the machine ha ben, did I not really notice the rest, so that I noticed many other things only today, like e.g. -fork quadruples a lot of oil (was yesterday clean) -fresh oil tank leaks (was said to be because it just replenished) -coupling grinds, does not separate properly, pulls despite pulled coupling (did I notice on the return trip first) -brakes neither front nor rear new (seen this morning) -tachho snail defective (seen today) For everything I have witnessed. What can ic The seller is only 16, and there was no guardian there, so the contract would have to be theoretically invalid, right?