First thing is to check first for any “known network faults - Try in 2 places
1) Try the “check service,”Area status webpage" (link at top right of this forum)
2) Then also try the “free & automated” Service Status number - 0800 561 0061 - which usually gives the most up to date info. and tells you of more local issues down to street cab/ postcode level.
Then are the issues only evident on wifi connections or do you see them at the same times on devices connected on ethernet cables? If you don't know, can you check to help diagnose whether it is just a wifi issue or it could be network connection/Hub related?
What Hub model is it? What are the various Hub lights showing/doing when this happens if a Hub3 is the base light a steady white(ish) or flashing green?
I do not work for VM. My services: HD TV on VIP (+ Sky Sports & Movies & BT sport), x3 V6 boxes (1 wired, 1 WiFi, 1 on PA) Hub5 in modem mode with Apple Airport Extreme Router +2 Airport Express's. On 250Mbps, Talk Anytime Phone, x2 Mobile SIM only iPhones.