Agreed! It's easy for previous occupiers to jack the price of sought-after resources up to ridiculous amounts as a final 'fcuk you' to the new occupiers. If you can't place contracts in an enemy port, you shouldn't be able to keep contracts in an enemy port.
I suggest that during maintenance following the hostile takeover of any port, all buy/sell contracts should be wiped. This would cut back on price gouging, something that we currently can't do anything about, other than to let their orders fill and wait for prices to reach a reasonable level again.