I have a monthly phone subscription, and I need to recharge it. Since I have not yet paid for it, the service is only working one-way. Meaning that I can only receive calls, but I cannot make any calls. Is there a word or phrase to for this situation?
You could use the verb "suspend" to mean:
to stop (something) for a usually short period of time.
You could say:
"The phone company (has) suspended (my) outgoing calls"
The technical term is "half duplex."
A full duplex channel has two way communications. A half duplex only enables one party to communicate at a time.
A "simplex" is a strictly one way channel.
You could say your service is currently unidirectional.
moving or operating in a single direction. (Google)
This relies on your reader inferring that inbound and outbound are directions, but I think most people will follow your meaning easily. I have actually used this word myself when describing the same problem to my phone company.