No internet and intermittent internet since 13 November

Since 13 November I have had either no internet or intermittent internet. First outage on 13 November following a storm resulted in 3 new hubs, 3 ONU boxes, 5 engineers to confirm a network issue. Internet working on 19 November. Next outage on 13 December so dad I have had 2 engineers. First one confirmed network issue to be resolved in 24-48 hours. No internet or intermittent internet called Virgin 3 times 2 advisors confirmed Virgin were aware of network issues yet, 3rd advisor confirmed no issues or outages and another engineer sent. He arrived Monday of this week and could not see any issues with the equipment in the house and spoke to his manager and network team who knew of no network issues. We are now on day 11 of no or intermittent intermittent internet. The app is mostly useless in saying everything is working correctly but last night it did give a message after doing a hub test that there was an intermittent issue. Can anyone advise how to get this issue escalated to someone who will fix it? Currently solid white light on hub 5 and no internet.