From what you describe, it suggests that you may have a signal problem that you would be unlikely to be able resolve.
Your best course of action would be to call Virgin and navigate to thinking of leaving, this will tend to get you to retentions and they can run tests on your line and equipment. If they are unable to resolve the issue then they can arrange of an engineers visit.
Option 1 then 4 then 5 should get you through to retentions
150 from your Virgin Media phone or mobile or 03454541111 from any phone
Lines are open Mon to Fri 8am-9pm, Sat 8am-8pm, Sun 8am-6pm
You can't learn anything from a mistake until you admit that you've made it.