Here's what Bitget support had to say.... note their line "At that time, the price fluctuated greatly, so it was normal for the closing price to slip."..... I would be ok with a small bit of slippage but when I set my stop loss to $50 and I lose $150 I don't think $100 of slippage is acceptable!!
I've become a victim of such accident on Binance in 2021. I had set a stop loss but I got completely liquidated because the price got significantly pumped and dumped within seconds, which was enough to liquidate me but the funny part is that price became normal after a few seconds, btw Binance closed my position and liquidated me. This was a lesson for me and I started to believe that rumors were true, exchanges artificially pump and dump the price to liquidate customers and generate profit.
Take it as a lesson and never trade on futures again, especially with increased leverage and short positions. Just buying and holding the coin is the best and safest approach (withdraw to your wallet for more safety).