My email addy can't be changed on my family's computers - what's up with THAT?

Yahoo has had mail trouble for days, %26 I'm not sure this is a Yahoo problem but my family says it has to be so here goes...I recently asked 3 of my family members to start using my Yahoo email instead of an email address from another provider that I want to drop. First my brother reported that he had changed my address EVERYwhere in his computer %26 now he can't click on my name %26 it fill in my NEW address, he has to manually type it in. Next my sister, who uses a third provider, says she's changed my addy EVERYwhere (groups, individual listings, etc) and she clicks on my new email in her address list to send me messages, but even though it shows my new address in her address book, it sends a message to my old address. Both have totally deleted me from their systems and started from scratch, but their computers simply won't 'recognize' the Yahoo address -- can someone tell me where to even begin to figure out what to tell them to do to solve the problem?

I just don't understand

My email addy can't be changed on my family's computers - what's up with THAT?free anti virus

Either the server is offline OR Could be several things. Go through my list and try to fix it.

1. Yahoo locked you out for excessive usage usually 48 hours. Time will fix that.

2. You have ISP provider related to Yahoo. Like Verizon, SBC, BT, etc. Then get Yahoo