Hi @Jgrahamclare thanks for your post although I'm sorry to hear of your difficulties getting your Volt upgrade.
So if you already had a SIM Card with O2 prior to the Volt benefits being applied, this is something you must go through O2 with. Once they've processed the activation on their side, it usually takes about 14 days for you to receive the speed boost on our side.
When you contacted O2, what was their reasoning for them to direct you to us?
Many thanks
Tom_W