I am using Mail Chimp for a few months. It was working fine and as it should do always. I have used Mail Chimp forms plugin on my site to gather new subscribers for my list. All of this was working fine. But I started another campaign and though of collecting mobile numbers too. When I used a service called Contact US. They supported custom signup forms and I built a pop-up form there. When I attached that into my site is was working fine. But the list was not updating in my mail chimp account. I have enabled mail chimp integrating into ContactUS, but it's not working. I don't know what's the reason? But I have to sue ContactUS to gather my leads rather than MailChimp.