As a new customer I was angered (but sadly, not surprised) to receive sales calls almost immediately after starting your phone service.
Of all the options available for digital voice, you don't offer what we need the most: a Whitelist feature.
If you're unfamiliar with what a whitelist is, it's basically the opposite of your 'call screening'. Under whitelisting, only callers that we specify will ring the phone. Everybody else goes directly to voice mail.
Be innovative. Be brave. Offer customers a way, once and for all, to block all unwanted calls without also blocking the people we love.
A disgruntled customer