Thanks for the number, but they directed me back to customer services since they could only activate my Hub 4. I was forwarded to a call centre in the Philippines where they informed me that my Hub 4 power supply had still not been ordered yesterday, for a second time, and proceeded to do so. Unfortunately I was not surprised, but left even more annoyed.
After a protracted discussion to confirm billing and contract implications, they temporarily downgraded my broadband back to 350 Mb, informing me that my new contract deal would remain in place when I activate the Hub 4, after receiving my new power supply in supposedly 4-5 days. My Hub 3 was still not activated and I was told I would have to wait up to 3 hours, but promised a call back to check.
No longer believing anything and wanting to avoid another day without broadband and more hours on the phone, I called again to get through to the UK retentions team to explain the situation and reconfirm that everything has been done correctly. They forwarded me to to a broadband support agent based in India who seemed more competent, and ran some tests while we had an extended wait for the Hub 3 to activate. Apparently, the activation systems are now working properly again. Thankfully, my broadband is now working again and I can only hope that the Hub 4 power supply is genuinely on its way, and that the subsequent Hub 4 activation and account upgrade back up to 1 Gb will go smoothly.
After spending about 8 hours on the phone in total, it really is luck of the draw with VM's phone support, and clearly some teams/offices are much more competent than others. Just utterly shambolic for what should have been pretty straightforward customer service tasks.