Worst service and ****

I just had a lady phone me could not hear her name and the i asked her because she phoned me and i can never get ha hold of them when i phoned why i am paying more for my contract now after i explicitly asked them if i was paying less now and they said yes. The lady kept saying its not her problem and refused to give me her name she was very rude to me i asked to talk to het supervisor and she kept me on the line for 17min and not giving the phone to the supervisor she just later said she is putting the phone down and did it.I just want to know why i am paying more after it was said i will be paying more and want to lodge a complaint against that lady. Thank you.