I5 11400 upgrade kit

Okay so I previously bought a upgrade kit from Evetech and Apon receiving the items I noticed the motherboard I received had a lose USB hosing and the static plastic was not sealed, this made me think that Evetech sent me a second hand motherboard, I contacted them immediately and they advised me that they only sell brand new computer components. I sent the setup to RBS computers in Port Elizabeth and they advised me the motherboard is damaged the computer is not posting, contacted evetech and they advised me that the damages occurred from my side, a motherboard that was not sealed is now my problem. Evetech goes on to say they can provide a damage report for insurance claim, how can I now claim for second hand goods that I bought brand new from Evetech. I mean I spent R11000 at Evetech expecting to get brand new components. I'm now siting with a headache trying to get either my money back or BRAND NEW components from Evetech.