I'm having this same issue with my husband's account. He had ~35k miles that in December the website said expired March 18, 2016. I went online 2 weeks ago to start planning travel to use the miles, and his account says 0 miles. He called and was told the policy switched from 18 months to 6 months of inactivity. He was told if he flew within two months they'd reinstate the miles. That is total crap as they are his miles and this is their error to just take them and not notify us of the change.
It sounds like you've all gotten your miles back with a phone call or BBB compliant. I guess we'll call again and hopefully get someone else. Any other advice? I don't have a screenshot from December, though we do have a statement from September (I know, old) showing the miles value and March expiration date.