Airset email delayed/blocked in Yahoo - others too?

We discovered this problem a couple of days ago. Apparently starting last Thursday, Yahoo (whose servers were accepting our emails just fine for 5 years) decided to change their policy and started blocking our emails. They have not been very responsive to our efforts to cure the problem. We received one very cryptic response from a contact in their email group. We have tried to get clarification but have not yet heard back from them. We are working to cure what we thought was their objection (currently we don't automatically delete accounts that yahoo bounces as non-existent email addresses - so for example, if an AirSet group member deleted their yahoo email account but not their AirSet account, AirSet will keep trying to send a daily schedule summary to the now non-existent yahoo email account and yahoo will give send back a "bounce" message, after this happens a few times, apparently they start to think we are a spam service and start blocking email from our mail server.

So we are working as quickly as we can to cure this problem on our end. In the meantime, we changed the router/ip address through which we are sending email and mail has started to be delivered to Yahoo users again, which is why everyone with a Yahoo email account has started to see some 2 and 3 day old messages, they were sitting in the outgoing queue and when we changed to a non-blocked server they started to be accepted. Since we aren't really sure why we were blocked in the first place, we can't be certain that this ip address won't get blocked in time. Believe me, we are working as hard as we can to get this resolved but we will need Yahoo to start answering our questions so we know what they want us to do. It would help to have AirSet users who have yahoo email accounts send feedback to Yahoo that we are indeed a legitimate service and not some spammer trying to sell viagra :-) and to please work with us to resolve the problem.