To initiate a return, you must inform us of your decision within the Cancellation Period by contacting Arduino's customer support and clearly stating your desire to return the product.
Arduino customer service will provide you with a prepaid shipping label and the needed transport documents, which must be included with your return shipment to Arduino. This way the parcel can be identified in our warehouse successfully.
The return is free of charge and managed by a carrier.
You can either drop off the package at the closest pickup point, or contact the carrier and arrange for them to collect the package from you directly.
The conditions for accepted returns are:
Arduino accepts returns only within thirty (30) calendar days from the date of Customer’s receipt of merchandise. If you purchased the product from somewhere other than the Arduino Store, please contact that reseller. In case of defective products please refer to the “Warranty” section below. In case of return for withdrawal please refer to section 9 of the General Sales and Conditions.
You can review the full document here.