Bathroom installation

Hi I got a building firm in to refit my bathroom. When they came they ask if I would like a Bathstore to do a design which I did and I went to shop to pick items. When agreed to it the bath I was meant to get was 1690mm long and 740mm wide then the project manager come and said I couldn’t get the bath but showed me another bath similar to the original one and I said yes but unknown to me the bath I got was 1700mm long and 750 wide then they installed un known to me they had cut my new when I questioned them about why they cut the bath they said they had to cut it to fit my shower screen because of where the window was. We all new about the window and I knew I would have to have a folding screen because of this and so did the store and firm but never once did any of them tell me my bath would need to be cut now the screen doesn’t sit properly on the bath. I then ask the project manager if he had put the smaller width bath would he still had to cut the bath and he said yes. I don’t Know if a new bath should be cut or not, as now I am thinking that now they have cut the bath it is now void in the manufactures eyes thank you