Why isnt Comcast available in my area?

I checked on line typed in 93725 my address 5630 south cedar ave It came up with http://mobile.digitalcommercenow.com/OfferListing.aspx?filter=4&SID=d1ea3c1f-b582-4540-a679-c122acf9a410 Comcast Internet,when I called them they said it wasnt available in my area!why is that??
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