Vodafone UK overcharging on their shortcodes?

I had an anonymous tip called in this afternoon about Vodafone. The caller, who works in the UK mobile industry, close to major aggregators, claims that for the last 6 weeks, Vodafone UK have been charging users not just for the MO (the originating message) to a shortcode, but also for the MT (the return message) AND the premium billing message.

So, for example, if you sent a text to a £1.50 shortcode, that would cost you 12p. Then you’d also be billed £1.50 by Vodafone. All is good. However my contact alleges that Vodafone’s billing system has also been whacking the customer for an extra 12p. The total cost to the customer, in this example, being £1.62. Not good. My contact is not sure if it’s isolated to PAYG or a whole platform issue. If the contact’s tip is accurate, that could be quite a lot of additional millions of pounds charged by Vodafone.

Are you a Vodafone customer? Used any shortcode services recently? Can you check your bill for me and put this one to rest? Likewise if you’re an aggregator — what’s the story?