comcast to yahoo email scam

I got one of the scam e-mail and clicked on the link (7 or 8 months ago).  It took me to what I thought was the true login screen for Xfinity.  I logged in and it took me to the comcast e-mail page.  But now, scammers can read my e-mail.  I have changed my password twice at the xfinity home page.  I have had about 6 hours of work done on my computer via remote with tech people such as virus companies.  After all that, the scammers can still read my e-mails.  They take over an e-mail and change a letter in the senders name.  This was done as recently as today.  How can I fix this?