Buy price 40% higher than requested £200 down?

Monday i bought kosmos energy shares £600 @ $2.83 but trading 212 bought them @ $3.42? They have never been anywhere $3.42 since February. Your app has cost me over £200 so far. Why buy @ $3.42, where did this come from?
Immediately i was £75 down, share dropping constantly, how can i sell when trading 212 bought at the wrong price? Am i the only one or is this being looked at?

If you placed an order before the market opened then the shares may have opened at a higher value after the weekend.

There would have been a huge spread and the price may have dropped quickly right after market open, looking at the graph it looks like it quickly took a brief dive.

The green block on the graph is the market price, when you buy shares the sell price is lower or the same as the market price (ask price).
Also you may start negative if Tax/Stamp duty was applicable to that stock.
The pound may also have strengthened against the dollar after your purchase.

Those shares where $3.05 on Monday morning.

From my observation Monday mornings are very volatile so a pre-market open order is rather risky.

Overall if you ride the stock out on a Long you should make profit back again as the economy recovers if the stocks previous 2019 performance is anything to go by.