Got a call and there was only piano music playing.  I waited and said "hello" thinking it would start a recording.  Nope - just piano music.
??????????????

I suppose that you have a Microsoft TechNet Plus subscription that is up for renewal. I googled this number and others have posted this response.  Like you, I had a vm that just "hung up" after a couple seconds.

Confirming it is indeed Microsoft calling about TechNet subscriptions. They left an automated voice mail for me offering reduced pricing for a subscription renewal.

All i has was Misic when I picked up there number.
There auto dialer must  broken...

Got this call twice a day over the past two days.  Yes we have several TechNet subscriptions that will expire at the end of the month, so I'm assuming from other posts that it is Microsoft calling us about that.  My receptionist answers and gets music that plays for about 15 seconds and then the call disconnects.  I suppose I'll have to renew our subscriptions just to get them to stop calling and bothering my people.