1a) Pull the battery and put it back in. If you didn't do this, you may have not gotten a hard reset.
1b) Go to (Settings/Tools -->) Options --> Advanced Options --> Applications. If Ramble is listed there, highlight it, hit the Menu button and select Delete. If it is NOT listed, hit the Menu button and select Modules. Look for any Modules related to Ramble (they should have Ramble in their names). Highlight them, hit the Menu button and select Delete.
2) You can only SMS one person at a time without a third party app (I don't know of any).