I had postnatal depression after having my son in 2015, and after my maternity leave was all used up, I requested a meeting to discuss returning to work gradually. I met with my line manager and the boss and asked to be able to return to work gradually, starting at 2 or 3 days a week and working up to going back to my full time role. They agreed to try this for 3 months and then review it to see if it was working for evryone.
Today I requested to increase my hours and I have been told that my contract is now only for 2 days a week and they dont have the budget to increase my hours. They said I have been granted flexible working which has permanently altered my contract.
I never agreed to changing my contract permanently. I never saw or signed a new contract. None of this has been put in writing at all. They appear to have misunderstood what I was asking and now it seems to my my word against theirs.
What are my rights?