I have another text point.

It costs me money to send a text. If you text me on the 2nd of the month, my credit may have run out. My credit card ticks over on the 7th. I therefore put credit on around the 8th of the month. I try to respond to what I have to after that point, but occasionally forget.

Usually invites I can click accept/decline on facebook or text back for more details (if needed). I usually RSVP. Sometimes life does happen though, including my tightness with topping up my phone strictly every two months, and if I don't know you well enough to see you or have your home phone number to call then it may get forgotten. I have ignored a recent invite for a meal out - I didn't know the person sending it (the daughter of an acquaintance) so didn't even read it. Or them. There were multiple messages. I have strict junk filters and am very angry about my e-mail address being given out. I read it too late to respond (a half-hour after the meal started) and would probably reply with "Do not use this e-mail address, I have not given it to you, and certainly learn how to use the BCC box when e-mailing a bunch of people who don't know each other." Then forget about RSVPing while I ranted.