My internet keeps dropping and disconnecting

I have two WiFi internet accounts named on my xFinity account.......one is from 5 years ago (Arnold) and is a very weak signal but still active.  The other is the WiFi address name I've used for the past 5 years (Joyce's Network).  I've had numerous login issues this past month and a xFinity rep switched my account back to the old username (Arnold), it keeps dropping and disconnecting.....can anyone help????????