Unfortunately shipping via UPS to Canada is the worst for Canadians. UPS almost always tacks on Brokerage Fees and such easily doubling the cost of small items. UPSP is better however you need to pay extra for Tracking Numbers.
As for the purchase there is always a matter of trust in both parties when selling and buying. Using third parties to ensure each person sends and receives a working product may be too much time and effort especially for selling items such as angel eyes. It is a risk a buyer and seller takes especially on forums. It is also the reason why people purchase vehicles like CPO and used dealer vehicles rather than purchasing privately. Some are not willing to take that risk.
As for what would be fair. Since neither one of you can really prove who would be responsible you can
1. File claim with shipping company. Split difference for the cost if any.
2. Send item for repair and split the repair cost.
Hope everything works out.
Vishnu PROcede V5 Rev.3 | Helix Intercooler | Vishnu DCI | Forge Diverters | AR OCC | AR Catted DP | Bastuck Quad Exhaust | Aero Front Lip | Mtech Sideskirts | BMW 269 Wheels | 10&12mm Spacers | BMW SSK | F1 Autohaus LED | Rear Fog Light Mod