Discord now doesnt allow vietnamese's phone numbers?

I have tried to verify my vietnam phone number, but after alot of trying, i didnt even receive any of the otp codes. So i contacted discord customer support service and they told me that my phone number was ineligible. Then i used my friend's phone number (he is vietnamese too) but it appeared an error which is unable to send message

Therefore, i used alot of my friends phone numbers but still apeared the error "unable to send message". The only way to verify it left is using ppl's phone number that i dont know (but still vietnamese). And yes still unable to send sms message. Only my phone number was able to pass that error but still cant receive it. I have tried to use a random sms otp code (UK phone number) from sms247.com and i did received it.

Even though i can still use my own phone number or friend, family, or vietnamese's phone number to verify before. What are u doing discord? Are u really doing ur job or just sit at there? just fix it

Edit: its almost 10 vietnam phone numbers that i have tried