Organizing and accessing contact information in Outlook.com
Hi, I’m facing similar sort of problem however my experience with this site is that it hardly helps. For me this issue is encountered due to migration into new outlook.live.com from 1-Nov-2016, it seems that beta version of this site which is not completely tested but released to wider users. Along with that this decade is known for DATA and by looking at so many issues seems that MS is unable to handle and take care of important user DATA properly.
So you can try below to order to raise it with Microsoft. I raised once and they are responding by mails at least asking more details relevant to this issue. So hope similarly this 'Help' option will help you... All the best!!
After login into outlook.live.com click on '?' - Top right side of screen
At the bottom of the screen you will see 'Help' option - click on it in order to raise this issue to Microsoft support team...