WestJet complaint: Lost item on board

I flow business class from Hamilton to Calgary flight WS533 – PNR code YHGJZD sequence 00104 and ticket 8382178059584/1. Upon deboarding, I realized I left my electronics bag in the pocket in front of me – I asked the agent to get my item and she instructed me to call Calgary baggage and they will get me item for me. I called repeatedly without answer or help – I then after multiple weeks received a call from their group advising me they had my item. I had the agent look through the bag to inspect the items and everything was there. She asked me to fill out a lost baggage report – the original agent did not ask me to do this. I did the report within 24 hours 29929321. Again nothing from Westjet, I kept getting emails telling me they could not locate my items which is impossible. Finally after many calls a manager named Sherry called me and said they accidently donated my item. I asked for compensation and Westjet keeps hiding behind a hidden policy that they are not responsible for items left on board – however they have a process and team in place that either donated or stole my items. I have the voice message as proof they had my item worth over 1,000. This is wrong on many levels and I want westjet to do the right thing, at this point I believe the agent saw what was inside the case and decided she wanted it for herself.