Think I got scammed by a dealership

Hello,Two weeks ago I bought an used Kawasaki Z750 2008 with 28k km from a dealership. I was told that the motorcycle was still in very good condition.When I took the bike for a testride everything seemed normal, shifting was smooth, no weird noises and overall a good experience. Coming from a smaller bike I didn’t go crazy on the bike of course so I didn’t go higher than 6k rpm before shifting. The next day I came back and purchased the bike for €5250,- and on my way home is where the issues began..Suddenly a FI light showed up on my dashboard, so I took an uturn and went back to the dealership. They read out the motor management and said they reset the error light, but were really vague about what was wrong. I drove back home without problems, until the next day where the light showed up again..I didn’t really notice any effects so I just rode a while to see what could be wrong. Came to the conclusion that the bike runs great in the lower rpm’s but whenever I get in the higher range it runs like shit.. if I let go off the gas for a second the bike stalls and if I shift it feels like I go down a gear instead of up because I barely get any speed.I can’t even contact them right now because the shop is closed due to vacation until august 6.. I do got 3 months of warranty. I feel scammed because I wasn’t told the bike had these problems and now I spend quite a lot of money for a bike that runs crap..What are my rights and what should I do? Is there any chance I can get my money back or am I screwed? Live in the Netherlands. via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/cjrdvq/think_i_got_scammed_by_a_dealership/?utm_source=ifttt