It is quite simple...you've got to wake up and smell the coffee! Once management get a whiff you are about to capitulate and give up...you are quite simply knackered! If I was running your firm now I'd refuse to pay you ANY pay rise...simply because I think I could get away with it!
Get organised and fight back!! Strongly worded letters and emails won't get you anywhere, my friends!!
Nine times out of ten management ALWAYS back down when you show them your mettle!!
DO IT!!