Internet drops, technician came out and now its worse!

How can I contact comcast and speak to a person?  I want someone to check on the Comcast side to see what is wrong.  I want them to monitor the connection to see what is happening.  A technician came out replaced  connections, replaced a splitter, replaced MOCA filter outside (checked cables outside at the house, at the street and inside the house.)  All green lights he said.  That was Tuesday.  It's Thursday and now it is worse, drops all during the day!  I work from home and this is unacceptable!