Intermittent broadband outages

My internet connection went down yesterday, in the Stockport area. Trying to find out what was going on I eventually received that there was a problem on the network. Connection returned yesterday evening and still worked until midmorning today. It went down again and this time I was told I needed an engineer visit. The connection is working again now. I suspect that I never needed an engineer visit so obviously it would be good if I knew what was really going on. I understand that phoning a Virgin phone number causes some kind of reset so I had better not do that.