I should add, I didn't want to upgrade, simply wanted the Data cut off until refresh date. Conveniently, not an option - and if even 1kb is used on any given day, £3. Since the "mobile data" switch on most androids still for some reason lets packets through, was trapped into a more expensive contract. Can't believe I've fallen for this.
Thanks for posting. Sorry about the confusion regarding the tariff change.
I upgraded my tariff the other day and the information is on there to say it's effective from your next refresh date but it can be missed if you proceed through the steps quickly of course.
I'm not sure why your new tariff didn't kick in though. I believe you have have called in since posting and had the correct changes made this time so hopefully you don't get any further unexpected bills.
If you find you've exceeded your data again then the best option is to purchase more data as this is instant. Take a look at our Virgin Mobile Pay Monthly Data Add-Ons help page for more information.