sorry, I don't understand this part:

However, I always order to the online store's own office directly (usually without even creating the account - instead asking an employee),

you mean ordering from a store's website that also has a physical store nearby? and by asking an employee, you mean asking in person at the shop, right?

if so, I think that would work here too. but most of my online purchases are from shops that don't have a physical store, maybe at all anywhere, so I can't apply this technique