dǎ diàn huà shí shuō qīng yǐ jīng děng le duō jiǔ, duì fāng gèng róng yì pàn duàn shì bú shì shè bèi wèn tí

打电话时说清“已经等了多久”，对方更容易判断是不是设备问题。

When making a call, clearly state how long you've been waiting, so the other party can better determine if it's a device issue.