At regular, though infrequent, intervals I receive a multi media message in my inbox from 'δ@' which has no content. The message is completely blank. I do not have such a contact and I receive mmms so little that I'm sure it cannot actually be a real message from someone I know.
I have a HTC Desire with Android 2.2 on Orange (UK).
What is this and what can I do about it?