Hi, can someone assist me as to why my imessage phone number isn't activating or working? it will only activate using my apple ID. But I wanna use activating only my phone number. Anything we can do to fix it?

First, check to know whether you have an SMS plan enabled at least for One SMS with your carrier. Contact your Carrier (Cellular Service Provider) the agency who issued the SIM to you

If your iPhone is used with a carrier not found in the wireless carrier articles, make sure you can send and receive international SMS. (One SMS Only)

See the pic below

4 Step Process --> Turn off and restart iMessage and FaceTime (The order/sequence is very important)

1. Go to Settings > Messages and turn off iMessage.
2. Go to Settings > FaceTime and turn off FaceTime.
3. Restart your device.
4. Turn iMessage and FaceTime back on (Watch the GIF hereunder)

Yes, we have all tried the low hanging fruit disabling services and restarting :)

I have also been in contact with my carrier, and there's absolute nothing wrong with SMS. I am able to send SMS normally without any problems.

However this problem still persist. I get that annoying "activation error try again" every time.

So what to do?