Jak to rozumiec?

Temat przeniesiony do archwium.
If the faulty CD drive is returned within 30 calendar days of shipment, the replacement would be free of cost.

Moglby mi ktos przetlumaczyc?
Jeśli uszkodzony napęd CD ROM zostanie zwrócony w przeciągu 30 dni od wysyłki, zamiana będzie bezpłatna.
We would be happy to process the request for a replacement part. However, the part is a collateral part. This implies that the replacement of the defective part entails returning the faulty one. If the faulty part is returned within 30 calendar days of shipment, the replacement would be free of cost under warranty conditions.

Powiedzcie mi jak to rozumiec. Od kiedy licza 30 dni?
od wysylki