The simple answer to this one is yes, you need VM Broadband as the V6 Box is a Virgin Media product. You can't have products/services from two different providers at the same time.
That would be like asking Apple for a new iPhone 7, but asking them to remove the Apple App store and instead install the Google Play store. You're best bet will be to instead of complaining, perhaps try checking to see if there are any known issues or maintance taking place in your area as this could have an effect on your service.
I know from expereince, when there is maintance taking place in my area, they usually do it at the same time each time. That being mid-day for me.
There is no reason why you can't take broadband from another provider, I am unsure how this would effect the V6 box mind you, technically if it connects via wifi then it should work, being as most users use another router anyway, unless it checks your IP to confirm its a VM connection but I would doubt that
My speeds in the evining drop to between 3 & 8 mps. The 200mps I pay for is fine most mornings.
Complaining gets me no where. Over Utilisation ! I am getting a credit on my bills but what I want is constant, reliable speed.
Does anyone know if I must have VM broadband to go with my V6 Box.
Can I dump VM SuperSlow BB and move to another BB supplier e.g. BT ?
No you don't. I have tested my V6 box and it works via wireless with my BT Infinity line.
I was like you - The max I got was 120mbps over Ethernet, I was told that the problem was in the street and there was no way they could say when it could or would be fixed. - so I left within the first 14 days. I asked if I could come back and for them to look into it - and that I wanted a credit too but I never got a reply so I sent the gear back in the supplied bag.
The Tivo however, as I told VM finally is top notch, in fact it's so good overall Sky are playing catch up with Q by updating it so it does the record 6 watch a 7th also.