is correct.
texting is a country code plus a mobile phone number. Pakistan's numbers usually start with 3, so you should remove .
It's very cheap to make a phone call from Pakistan to China, which does not exceed RMB 3 cents a minute, but it's very expensive to make a domestic call.
sometimes you can't get a text message.
it's better to contact customers or send emails by VoIP.
I work in Pakistan, and I can send a message if I have any questions.