I buy things online, and ems express sends text messages before the seller arrives.

This is nothing to be surprised about. That's the seller's service. Mine has been signed for two days. The seller is still texting me to remind me that the express parcel has arrived. I'm confused. I carefully checked the seller's shop and the single number, and signed it two days ago.

This must be the reminder service of the store. Have a plenty of set, express unified delivery the next day, or automatic SMS reminder on the third day.

Wow, I will also check the EMS mail. If you like, you can also post the single number. I can check it for you. Maybe, my search is different from yours.