Should I call or send a message when mailing the Putonghua certificate?

Usually I make a phone call and send a text message, but no one answers.

Putonghua cards are generally issued by couriers when mailed, and the general contact method is to call or send text messages.

Short message, abbreviated as SMS, is a text or digital message directly sent or received by users through mobile phones or other telecommunication terminals. The number of characters that users can send and receive SMS at a time is 160 English or numeric characters or 70 Chinese characters.