WhatsApp Business not sending OTP, “Call me” option greyed out — stuck for 3 days

Hi everyone,
I’m trying to set up WhatsApp Business on my iPhone, but I’m not receiving the OTP verification code at all. This has been happening for the last 3 days.

Issue details:
I’m using WhatsApp Business, not regular WhatsApp.
I entered the correct phone number with country code.
SMS OTP is not arriving.
The “Call me” option is completely greyed out, so I can’t receive the OTP by phone call either.
I already waited for the timer and tried again.
I restarted the phone.
I checked mobile network and internet.
I tried reinstalling WhatsApp Business.
Still the same issue.

I don’t want to keep waiting for hours because nothing is changing.

My question:
Has anyone faced this issue where WhatsApp Business OTP does not come and the “Call me” button stays greyed out?

What fixed it for you?

Was it a WhatsApp temporary block, carrier/SIM issue, device issue, or something related to switching phones/data loss?

Any suggestions would really help because I need this WhatsApp Business number for work/customer communication.

Thanks in advance.