Need help with my mf 8690

Hi guys

So we have a mf 8690 from 2013 today we encountered a pretty big issue that never happend the tractor was ideling at 1200 rpm and no matter what we did nothing changed also it doesn’t go into gear drive or revers the button that allows you to use the gas pedal seems to not work but it works I don’t know how to explain that but the tractor goes foreword if you put the lever on drive and move the hand pedal or whatever it is called back which should move the tractor backwards but somehow it moves forward. I don’t know if this is the right place to ask if it isn’t could you guys maybe tell me where can I ask someone. Also sorry if my English is bad it’s not my first language