Is Twitter really "lying to get money" here? They're telling you that you can build your brand on Twitter. And you can. Is it misleading that they don't have a little asterisk that says at the bottom in fine print, "but we may take it away if someone else has a trademark on your brand name"? Yeah, maybe. Is that fraud? Ehhh... I'm not convinced.
IANAL, but my reading of UK law is yes. The relevant law is section 2 of the Fraud Act 2006 -- http://www.legislation.gov.uk/ukpga/2006/35/section/2
Fraud is (I paraphrase) lying to get money. It doesn't matter if the person you're lying to isn't the person you're getting money from.