Refusing and returning
Paying only on arrival means you can back out for free until then.
Until you pay
Say on the phone that you have changed your mind, or tell the driver you do not want the package. That costs you nothing.
Once you have paid
A crushed pack or the wrong product: send an email to contact@unguela.shop naming the product and the phone number used for the order. We come back with what the distributor in your country can do.