VM using my junction box for neighbour?

Hi I am hoping someone can help.  I witnessed on my Ring Doorbell workmen on my property near my junction box.  Apparently my neighbour is signing up for VM and the external company being used want to use my junction box to connect the cables.  This means my garden being dug up again for the cabling.  Is this allowed?  Surely more wiring than needed in my junction box is not advisable? Any advice.  The neighbour has asked for his junction box but they said it's easier this way due to the main Internet junction box being over the road and that means digging up the road? So they will just use mine.  They have not asked for permission to gain access to my property or juncion box.