I'm experiencing a similar problem to one others have posted on here. I can't ring one of the numbers in my contacts - when I call it, I get a series of sharp beeps then I'm cut off.
I've checked with the other phone and I'm not a blocked caller.
I did notice that my phone had put strange spaces into the number as it was listed, but I deleted and re-entered the number and it's fine now. Regardless, I've tried dialling the number from the keypad and I get the same result.
My phone is an iPhone XS and I don't use iCloud for my contacts.
The problem only appears to be with the one mobile I try to call, and sounds very similar to recent problems listed on here, but the threads don't indicate whether this has been resolved or provide a resolution. The number I'm calling is at my place of work and it's very important that I can call it. My husband also has a Virgin mobile and he can get through to it no problem.