I know it may be a side-topic, but considering expertise shown here, and if OP doesn't mind:

I have a different problem Cellular connection. The thing is, that I'm using a data-over-3G provider, that doesn't offer legacy cellular functionalities (voice, sms, etc), only packet transmission. Now, once, my son tried to send random SMS (few dozens, in fact) from that device, which, of course, failed.

Now, everytime I use that device and enable cellular, every 2 minutes or so a message about "failed to deliver sms to: <contact name>" appear. I tried deleting everything from conversations, to no avail. i can't find an "outgoing" category in Conversation, too, where I could delete messages waiting to be send (like we have in mail client), for a life of mine.

Of course I'm aware that inserting a "normal" SIM card and allowing those 60 or 70 messages to send themselves correctly could be a solution, but it's not something I would prefer to do

Thanks in advance for any tips on how to get rid of it,