Issues with Membership2 Pro

I'm now having 2 issues with Membership2 and the site owner is getting increasingly frustrated. The first issue was that the Mailchimp add-on was causing a 500 error when new members were added. The agent I did a live chat with gave me a new mailchimp php file to upload, which I did, but it didn't solve the problem. He said it was a bug that was going to be released in the next update.

The second issue is that 1 member in particular cannot log into the site. I looked at it further and realized that, for some reason, the member had an expired membership...even though they were added within the last couple of days. I tried to manually set it to Active, but it keeps reverting back to Pending/Awaiting Payment.

Any ideas?