I just figured I would come and post about this so people know. After I received two mms messages and I replied back --and getting a bunch of "who is this" replies I had my husband do a "test" mms message to me and to my son. I replied and they both got it. I looked all over the phone for a fix but none. Well..I called Verizon and they looked it up and the rep told me the only work around this for now is to make a new text message and reply to the person. She also told me to make a suggestion to Blackberry about this issue and maybe they would do a fix in an update or something. Anyway I just thought other users of this phone should know this because it could be embarrassing depending on what you reply back lol! You could be replying back to 10 different people what you only thought you were replying back to your spouse or friend.
i'm having opposite with Sprint. Can send group messages, but unable to receive group messages. If they send a group message, only comes across as individual message. Friend on ATT can receive and reply to group messages. Another friend on Sprint has same issue. Sounds carrier specific.