I've edited your poll as the original options didn't make a lot of sense.
Welcome to the forum.
The answer to this is a little complicated - to an extent it will depend on the nature of the title deeds to your house, and whether they confer any rights on your neighbours that might allow VM to do this.
Did they have to come on to your property in order to do the installation?
Is your house a terrace, semi or detached?
Do you know your neighbour, and did they discuss this with you in advance?
I think in general terms the way they have acted is probably not legal, and it might cause you problems later if you come to sell the house and it looks like a wayleave has become established, allowing your neighbours the right to drill holes in your walls in order to maintain/renew their cable TV installation.
You may have to consult a solicitor, and get a letter sent to VM threatening legal action to recover the cost of removing the cable and making good the damage caused, unless they send someone round to remedy it within 28 days.