Plus500 Broker Manipulated Cocoa Futures Prices, Charged Excessive Rollovers

I opened a short position in cocoa futures at 9000. The price went up to 10100, so I waited. The next day, the price dropped to 8900. However, my broker held the price at 9800 and didn’t update it, moving independently from the market. I contacted them to ask why, but they gave vague answers. Three days later, they finally adjusted the price to the real market level. However, they charged us a €68.6 rollover fee for a 0.10 lot and a €205.8 fee for a 0.3 cocoa lot.