Next doors' works left my own box in a mess

A few weeks ago, our next door neighbours had an issue with their Virgin connection, and the engineers asked if they could connect to our external box while they fixed the problem. A few weeks later, and we have come back from holiday to find the box open, its insides exposed, and the cover and screws left lying around in the garden.

I tried to call Virgin but it just goes to an automated system that checks my connection. How do I speak to someone? I need an engineer to visit and get this tidied up asap.

Thank you.