Xfinity will not let me add a line despite an 847 FICO score

I recently responded to an offer for Xfinity internet and mobile services offered by an agent who knocked on my door. I live in a rural area and New fiber was installed in the area. I had fiber service from a competitor and a family mobile plan with T-Mobile with 4 lines. The price offered for both was attractive so I decided to move to Xfinity.  Internet change was successful but when moving mobile service I was told I could only add 3 lines and was not told that until after I had already transfered them leaving one remaining line with T-Mobile. I am now left with 3 lines with Xfinity and 1 with T-Mobile. This is the worst case scenario for me. I was told risk assessment determined I have to wait 6 months and try again.i have a FICO score over 840. My credit was never run and none of this was communicated up front. I don't understand how you assess risk. One more point, all phones were unlocked and I was not financing any equipment, just switching service. I plan to pay all early termination fees, cancel everything and share my disappointment with the neighborhood since I was asked to tell the neighbors when the sale was made. Very dissatisfied and will not consider Comcast or Xfinity in the future.