O2 introducing data limit in contract with no notice?

[Andy F]

Hi, my billing date is the 25th of each month and yesterday I received a text telling me that a data limit was being introduced to my contract from unlimited to 750mb.

Fair enough. Except when I spoke to them today they said it came into effect yesterday and they can do it without notice.

Surely they need to give 30 days notice to introduce changes like that, regardless of what their contract says. I presumed 30 days was a statutory right and if their contract stated they didn't have to give notice then that's a breach of those rights?

Just wondering if anyone with a bit of knowledge could shed some light on their stance on this one?

Thanks.