Our Guarantee — 100% Satisfaction. tnartsupply.com guarantee policy. If you are not completely satisfied with the quality of the merchandise you receive, you are entitled to a full replacement or refund. To return a portion of your order, we ask that you contact our Customer Service Department via email or call 412-683-4444 within 30 days so that the exchange, refund, or credit transaction can be arranged to your satisfaction. You must include the packing slip or a copy of your invoice and a note advising us of the reason for the return. If you do not have either the packing slip or invoice, or if the return must be sent by truck, please contact our customer service department for return authorization and instructions, and we will arrange for the return. Merchandise returned as a result of a customer order error will be subject to a minimum 15% restocking charge.