2006 Opel Corsa REV COUNT MALFUNCTION

Car is rev count is going up to 7 on gear change and wobbles making it choke. I decided to have it towed to the dealer who then advised that my clutch was finished. Although it gave an engine management error light while the petrol gage moved from full to 3 quart full then moved back to full. Please advise what could be the problem really.

I took my car in for a service 3 weeks ago, and then the engine management error light, took it back to the dealer they drove it for 15km without the light coming on and returned the car back to me.

Then it chooked 2 days ago, afer filling petrol and when I called them for a check they were full up until yesterday when I experienced the rev count and sound abnormalities. Pelase advise.