iPhone sending hundreds of auto SMS txts

I noticed on my phone bill this month that my phone had been sending literally hundreds of automatic text messages (SMS) to four numbers, at all different times of the day and night.

I'm in the UK, and the numbers it's sending to are -

07860 015000

07860 015001

07860 015002

07860 015003

They're all included in my price plan, so it's not cost me anything, but I thought it was strange and started to investigate. I had noticed my text message allocation had been going down, even though most of my txts are to other iOS users, so I mostly use iMessage.

It turns out those numbers all belong to Apple - they're used for activating iMessage and FaceTime. And the reason it was trying so many times, is that the number my phone says in "my number" (Settings > Phone > My Number) isn't actually my number. I noticed this a while back, but it won't let me amend it, and because I thought it was just there for my information, I ignored it.

So - I'm trying to activate iMesssage and FaceTime using my correct number. The number stored on the phone then tries to override that, attempting to activate the wrong number, which, of course, fails. So it keeps trying to activate - so far, having sent an average of 10-15 messages a day, over the course of 2 months.

The incorrect number on the sim card is because I got a new account with my network (3), then swapped my old number from my previous carrier to this card.

The only way to fix it is to get a new sim card, since I'm not able to amend the number stored on the sim.

The reason I post this is that this seems to be a serious bug with activation - if it can't do it, it should give up or at least tell the user that it can't do it. If I had to pay for my txts, it would have been extremely expensive - and I'm quite sure neither Apple nor 3 would take responsibility and give me my money back.

I got lots of help from peckerhead on http://forums.macrumors.com/showthread.php?t=1358677