Mystery secondary user on our account

I got an email last night saying that  'Our records show that a secondary user on your account recently updated their Xfinity ID.'  A 2nd email said that 'our hotspot' would be active between x hour and xx hour last night.

My husband is the only secondary user and he said he didn't request anything.  We've changed all our passwords but I want to know what's up with this?  What could it be?

Also...really hard to contact xfinity with problems like this...