Incorrect provisioning

When I did my self-install with the help of a phone representative, my modem was incorrectly listed on my account. It should be Arris Sb8200, not SB 8300. This mismatch seems to be causing issues with my connection/speed, but could be unrelated. I am not getting anywhere near the gigabit speeds that I am subscribed to; getting about 250 mbps download.

Can someone help me correct this please? @ComcastMorgan @ComcastAlly

Thanks