Have you worked there for 6 months in total?
Is there any age or medical reason for your reduced IT ability?
No i am 47 and didn't encounter computers at school so have little knowledge of them.
Ok no problem. There is no problem with you raising a grievance to your employer about the way you have been treated and in stating that you feel used and that you cannot return.Your employer should have a HR department who will tell you the correct procedure to follow.
There is no claim that you can bring against them in this situation though I'm afraid. The only claim would be based upon discrimination which does not appear to have happened here.
Please do let me know if there is anything further you would like to know about this. If I have answered your question I would be grateful if you would take the time to rate my answer. Thank you and all the best.