what not to do as a startup: cal[dot]com sold us on a feature that they internally knew they were soon deprecating we spent a month building something using that feature only to find out ourselves this week spent days trying to get in contact with someone from their team (we're paying users) we emailed their founder twice and got hit with an "unsubscribe" after later apologizing, their founder bailed on the call with our team at the last minute and had some entry level growth person take…