Absence of purchase documents (with ZappTax, the proof of purchase is the ZappTax resale invoice that is attached to the tax-free form).
No presentation of goods (the absence of a single item listed on the tax-free form may result in the cancellation of the entire tax-free form).
Goods of a commercial nature (left to the discretion of the customs service).
Tax-free form expired (forms are valid until the last day of the 3rd month following the month the form was issued).
Presentation by someone other than the person whose name appears on tax-free form.