Another company added almost same domain name as my company and linked it directly to his website to try to direct my customers to his website?

I have a small business. There is another small business in my area that does the same thing. We both have been in business for several years my business longer. My domain name is the same as my company. Recently the other company bought another domain the same a my company's and just left the ( s ) off the end and has linked directly to his website. My business is not the only one he is doing to. What should I do?