How to recover the information of an unlisted telephone number?

Hi! I am running my own business. I want a favor from you all. My issue is that one of my clients hasn’t made his payment since last four months and I am having his phone number only. I have searched for his address but was not able to find it anywhere as I think it is an unlisted number. But I really want back my money. Is there any hope to recover his full information?
Any help is appreciated.

 

Re:

Oh! Not to worry. One of my friend who is also a business man had also faced the same circumstances but he came across unlisted phone numbers which assisted him to retrieve the particular number’s information. Now he usually takes help of this service. I think you should also try this.
All the best.