Open letter to LinkedIn

Dear Linkedin,

I love your service. I really do. But your email-marketing sucks. Last two years you have prompted me, without success, to get to try your Linkedin Premium service. Each time I try to do that you ask me for my credit card information, which I don't feel comfortable giving since the "Free premium month" should be free and therefore should not be dependent on my credit card information. I understand that your aim is to trick people to subscribe to your service by forgetting to cancel after the free month. Honestly, I might be interested just don't push me.