On the 21 June 2012 between 18:51 & 18:57 I received 8 phone calls (the phone shows it was a text but no text was received) from 33779 and my phone for some reason sent a text back (no idea what was on that text) 7 times. I have no idea who it was from. To prevent further messages being received I've blocked the number through a phone app.

This text number is from Three mobile network it started happening to me after visiting thier site I like you play safe and ignore the number

This is caller is from three mobile network, they ask you questions if you have recentley visited their site

They seem to do this regardless of whether or not you've visited their site recently. It might be that accessing their (very dubious) android application counts - but I would be surprised if even three were that stupid.

Spam from Three. Which you get regardless of having used their crappy website to try and stop previous spam. Why do networks persist in this tedious behaviour? Even Three can't be stupid enough to believe that persisting in spamming after you've specifically been asked to stop is a good business model.