One of the upstream channels is showing a significant number of T3 errors which could be historical but impossible to say without the network logs to put them in to context.
I take it you have rebooted the hub.
You will need to contact VM for resolution, either by waiting here about a week until a VM Forum Team Member picks up the thread, or give them a call on 150 from a VM line or 0345 454 1111 for a quicker response.
I have been having this discussion with VM for the past 5 months since I went with these guys. It's all over the internet community that they always say upto and are hide behind this poor statement and consistently provide lower speeds than promised. They couldn't get me upto my 200 and getting 30 to 60 during non peak times. The only option for me was to escape the contract when they increased the price and it's the best thing I did. Now with BT that can't offer their max speed but at least it's more reliable, consistent and to be honest have not had any download speed problems. Good luck with them anyway.