Customer service lies

I'm so fed up with customer service.. so I was on the bring back program which ended and I wanted to upgrade my phone.. it was getting near when the extension was up and I phoned telus asking if I could extend it to this date when I would be able to get a new phone.. because there was no way I could pay the amount if I didn't bring it back.. they said no problem we can do that, called them again before i went to get my new phone and asked if I was still good to go, and they said I was and didn't owe anything.. so I get my new phone, get my bill and turns out they did NOT extend it and I now have to pay for this overage of a bill.. so I call them again asking if I could do some payment plan on it and the person I talked to said I could and that I had to call them back on the 15th which I did AGAIN.. and I lo and behold I was told I was NOT allowed to do that even though the guy before told me I could.. so basically told me a lie and now there's nothing I can do.. and the person recommended me to go to the store and see if they can do something for me... I have been with telus for a long time and this just absolutely made me so **bleep**ing mad.. to be told one thing and than the next tell me I can't do it because it's too late?! Idk what do