China and many countries have patent inquiry systems (please go to Baidu yourself, because if you give it directly to your website, the answer will be recycled by the system). You can use your application number to check the payment status and whether to send you a registered letter (with a receipt).
In addition, if you will apply for patents more often in the future, I suggest that you apply for a personal account on China Patent Electronic Application Network (please Baidu), so that it will be convenient to apply for patents and pay fees in the future (and save the mailing fee).