MARKET TRADING

No, as soon as another player accepts the deal, you will immediately receive resources)

99% of players who think that they did not get the items they purchased on the market have high command and items in their build queue are waiting on that specific resource. Purchased items are then consumed nearly instantly by that pending item on the build queue.

For rare materials I expect a level 1 industrial complex was started at the time of purchase.

Now if you put in a "buy order" for a resource then your money is held by the market, but the resource will not be delivered until another player or AI decides to sell and fill your order. You can always check the "my trades" section of the market and cancel pending orders if you wish to free the cash up again.

this was a player selling RM on the market which I then purchased, but I didn't receive the goods nor am I in the high command

In some cases two people can try and buy one item on the market at the same time. This will mean that one player will get the resources and the other will not. You should check on your "my orders" tab of the market and see if the order was executed, or if you now have a buy order for that resource instead.

ah yep, that might might be it, but why was my money taken then???

So if you tried to buy something that was already sold, you may have ended up with a "buy order" in place.

A buy order means that you offer $x per item for a quantity of items. The market will hold your cash in "escrow" so that when another player decides to fill your order the money is available. If your money was not held "hostage" by the market then you could easily spend all your money and not have enough available to complete the transaction.

If you open the market and look at the right tab it will show both current and executed orders

The total price column of buy orders is the amount held in escrow by the market. You can cancel the offer with the "x" and get that money back.

You can also scroll through the executed orders and see if you perhaps bought a different resource than you thought.