OP works 235 hours and gets paid for 235 hours.
This whole "not getting paid overtime" is very miss leading.
OP you are getting paid overtime, you are just not getting an increased hourly rate for the overtime you are completing.
If you only want to work your contracted hours then sign back up for the working hours thing and only work your contracted hours.
If you get paid for the work you do, there isn't really much to complain about.