Constant Calls from Legal Department

I get about 5 calls a day from this company and each time I explain to them that the person they are looking for is not me. They have obviously been given the wrong contact number. According to them, they cannot delete my number off their system. The solution? I must block the numbers. Problem is, these guys keep phoning from different numbers. It`s a nightmare.

I need them to rectify THEIR mistake and delete my number off their system.