MiWay Insurance - Leeches

MiWay are a bunch of leeches. I am currently receiving up to 25 calls a day from their call centre to try and get me to take insurance from them. In the beginning I used to answer the phone and tell them that I am not interested as I am totally content with my current service provider, but they just do not take NO for an answer. I have sent them several emails requesting for them to remove my number (have no idea where they got it in the first place) but this is just conveniently being ignored. Have also contacted DMASA who said they would contact them. This is now starting to get very annoying and even starting to affect my work as my employer is getting annoyed with my phone constantly ringing with calls from MiWay. They are just so persistant. If I decline the call, they wait 10 minutes and phone again and again and again.