What happened to all the features on the "Original" SimpliSafe?

Don't wait for an email response, they haven't been responding to emails much.  Call them, try calling at 9 am (ET) when they open, press #1 for sales to get someone to answer sooner.

Um....I can't imagine them taking away PINS.

Must be a glitch.  But even then, I'd be ticked too.

And call at 9am ET.

I just went to View Account on the Simiplisafe website.  On the left side of the screen it said PINs.  I clicked on that and was able to add custom PINs.  Of course I did this on my computer.  YMMV on a phone.

^ There used to be a third monitoring plan (19.99) that they discontinued - when SS3 rolled out in Jan 2018, they grandfathered some people who were on that plan, but I'm not sure everyone was grandfathered because there were several complaints at the time, so SS had to fix a lot of accounts (that users found were blank, missing features, etc) - this may or may not be the issue with the OP, but he/she has to call SS to find out.