Hi thorpemeister, thanks for getting in touch.
Sorry to hear you've encountered this problem when getting in touch via text message. The characters requested would be from your memorable security word - the one you use to speak with members of staff & not to be confused with your own password you use to log into your MyVM account etc.
If this isn't successful, then usually we'd request to go through alternative security checks with the account holder directly.
What were you getting in touch about, maybe we can help from here?
Tom