Dear Sir, i am very very thankful for your long reply, as it has helped me realize the problem i was having, i managed to come to an agreement with the dealer, as they did apologize to me, and stated very clearly that they have never changed a belt on this type of ATV, and that they made the same mistake twice, now, they put a new nut, and a new bolt, applied loctite to both of them, and also to the secondary, and put in a new original bolt!
I hope they torqued the bolts and nuts to the proper torque, as i supplied them with the values to torque it to!
I made about 50 kilometers after the latest service, which was on three days ago, and i hope that all will stay well, they said that they found no damage to the shaft, or the internals of the primary clutch, the atv has restored its original speed, and can go up to 90+ Km/H now.
I will test it some more on the trail on monday and see how it goes.
I am very happy you replied as there really is little information regarding these models

Btw, is your fuel guage accurate?
Mine sometimes says i only have half of a tank, i when i fill it up at the gas station it can only fit around 6-7 liters, and the tank is supposed to be 21 liters.
With kind regards from Croatia,
Bubi