It's either a spot market (i.e. immediate delivery) or a contracts market (e.g. futures, options, CFD). I don't think there is such a thing as a "spot market contract".
In this case the price spike happened on a spot market. The buyers simply needed more gas than was available for sale. So the profits simply went to to the producers that had any gas to sell.
Edit: this Reuters article names some companies that raked in profits:
The biggest winners were companies with access to supplies, including leading energy trader Vitol, gas suppliers Kinder Morgan (KMI.N), Enterprise Products Partners (EPD.N) and Energy Transfer (ET.N), oil giant BP plc (BP.L), and banks Goldman Sachs (GS.N), Bank of America (BofA) (BAC.N) and Macquarie Group (MQG.AX).
https://www.reuters.com/business/energy/results-tally-up-bil...
