Bogus contacts won't delete

My environment: I'm a Microsoft 365 subscriber and use Outlook Desktop for Windows (the paid version, not the free one). I sync my contacts from my outlook.com account to a Samsung Galaxy S21 and use the native Samsung email and contacts apps connected to the outlook.com account. Suddenly I have a problem with a couple of new contacts I tried to add. Upon adding a contact from my phone (just associating a name with a phone number), several minutes later the name and the phone number became disassociated as if I had never created and saved the contact. I added it back several times and same thing happened. This contact did not appear on my phone, nor did it appear in Outlook Desktop. But it did appear in the Outlook.com web interface. In fact, it showed up multiple times, once for every time I tried to add it to my contacts. These multiple bogus contacts cannot be deleted from the web interface. When I attempt to delete the contacts from the web interface (the only place they appear), I get the message: couldn't delete contact. I have since added a test contact to see if I had reached some sort of maximum contact threshold, but the test contact is hanging in there fine. This has happened now with two contacts. So I'm at a point where my contacts are not working reliably and it's a very busy time for me business wise for my contacts to be giving me trouble. Please advise.