2gb Internet promotion issue

Xfinity just became available in our neighborhood, and I signed up during the holiday promotion to lock in the 2gb for 5 years. Got all excited as I've been working on computers all my adult life and have 3 adult kids living at home gaming so to have fiber 2gb to the house was just what I needed.  First is I was told I was getting the latest greatest XB10 but when the guy showed up to install my internet he said it wasn't supported with the fiber connection, which was the first disappointment. He said the XER10 was just as good but the first thing I got back on a search to compare the Xfinity XER10 and XB10 are that both advanced gateways that support WiFi 7, but the XB10 offers superior performance with DOCSIS 4.0 capabilities, making it ideal for high-bandwidth activities. Wanted to know if this is true that the XB10 is not supported with fiber. Also when he hooked it up I told him I wasn't seeing the 2gb speed that I was paying for and he advised me that the speed test were based on what your device could pull so you may not see it on my test. I gave him the benefit of the doubt and just wanted to get to using my internet so I let him go. After he left I setup my online account and it stated I was in the 1.2gb plan and I could upgrade for an additional fee but still be locked in for 5 years but I knew I already should be on the 2gb plan. I called support and they said the website just takes time to update which kinda through me for a loop as I was a new customer and it should have never said 1.2gb. I loaded the app on my phone and it also says my current plan is 1.2gb and I could upgrade to the 2gb if I wanted to pay the additional fee. The guy on the phone said he connected to my router and was seeing the 2gb speeds but I am not and I'm afraid if I click on the upgrade to 2gb plan and rerun my test and its better that if I call support I will lose my locked in 2gb plan because I changed it even though I have the email confirmation stating I paid for a 2gb plan which is why I would have clicked on the upgrade in the first place.  I even went by the store and showed them my phone and he said I should be on the 2gb plan and not sure why but told me not to click on it either and they were confused and told me I had to call back in to support as he couldn't resolve it in the store even though he was the manager and saw it when I was logged into my account with the app on my phone. Anyone else having this issue?