I am getting these type of calls on a regular basis of late, and there is very little that you can do about it at present, unless you have full details of the company or person doing the calls.
You could report the nuisance calls to your service provider, in hope that they can offer assistance or advice. You might also consider looking at these websites, seeing if the offer a solution www.dma.org.uk www.telepest.co.uk www.whocallsme.com www.phonespamfilter.co.uk I have not used any of the links, so I do not have any experiences of the service they provide, so you will need to consider this!.
Personally I just inform the caller that I have not had an accident, and I or any members of the household do not require their services, and then replace the telephone on its receiver. There as been quite a number of articles in the newspapers lately, about insurance companies and similar establishments who are selling their customer details to 'ambulance chasers'. Some insurance companies are now saying that they will cease the practice if others doing the same do so!.