Call to one specific number ALWAYS busy tone

[Topazgirl]

I have an ongoing issue with calls to one particular contact who uses at&t. I can NEVER connect a voice call. I either receive an error message that it is busy, or a busy tone. The only time I can connect is using FaceTime audio and video. Messaging works fine. Can someone PLEASE HELP me figure out what is causing this to happen??

[Sprint_Ciara]

Hi Topazgirl ! That's odd. You're having issues with making calls to that number, however, texts and FaceTime seem to be working fine. Is this person able to call you? How long has this been going on? 

[Topazgirl]

Yes, they can call me like normal, no problem on their end. And yes, FaceTime and messaging works fine for me.  This has been going on now for months actually. They do not have me blocked, we’ve checked that. So I don’t understand why it’s happening and only their number. 
please help!

[Sprint_Jeffrey]

We will need to submit a ticket. Please send us a private message to further assist you. Click on my name to see the option.