Many of the plants purchased online in 2018 have died

It appears that purchasing plants online is becoming risky, because many of the plants purchased online in 2018 have withered and died rather quickly.
The only thing that remains are the pots. This is because the plants are not grown in the pots initially, they are grown in the ground.
When an online order is received, the plant seller will transplant the plant in a pot, and observe the plant for a few days
If the plant does not wither, they are sending the plant to the buyer.
However in many cases, the plants are withering after a week or 15 days . So it is advisable to only purchase hardy, easy to grow plants online