The wallet address change everytime you click the receive coin button. All the address are usable and are linked to your seed. You can list all the addresses generated by typing wallet addresses in the terminal of Sia-UI.
If you cannot see your transaction,
Make sure you are using the latest version of Sia-UI (v1.3.1), older version of Sia-UI will be incompatible with the current network thus not showing your transaction.
@haimeh222 As more and more A3 units release the lower and lower your profit. It looks like there are at least 150 more units for sale on ebay. Unfortunately that is what happens when you buy units from a company that doesn't release how many units they're going to sell. You'll probably get down to $10-$50/day and then even lower once 2500 more Obelisks release in May. Good luck.