Store rep couldn’t process customer retention offer.

Hi, so I went into an Xfinity store in Fremont, Ca on 11/6 to exchange my router due an issue w/wifi I had been having for a week. While talking to the store rep he looked up my account to see what plan I had (2gig internet only) & told myself and my husband who was there with me, that we were overpaying and that he could give us a better deal. That there was currently an internet deal at $89.95/mo locked in for 5 yrs with our same speed. Sounded great so we said sure go ahead and process it. We wait around for a few minutes and he even brings up how there is a great deal with their mobile phone plans, but we passed on that and still waited. Then he says sorry he can’t process it. That we can’t have it because we are current members & it’s only available to new members. Gives us our new router and says sorry again. Not cool. He really sold us on that offer & w/money being so tight these days we were excited for it. We have been Xfinity customers for years and I’m hoping someone can help me out and get me this deal. Again w/money being tight I might have to shop around & see if I can save money elsewhere. We were really disappointed when we left “empty handed” & just a router. Help please?