It will mostly depend on A) whether the seller actually sent the items or not (sellers can be suspended for several reasons, some of them are temporary and don't generally interfere with their order processing, and B) how you paid.
If you can be certain the seller hasn't, or won't, send the items, you will have protection if you paid with a safe payment method (eg PayPal, credit card), and can open a dispute to get your money back. If you paid by PayPal, you will need to log into your account, locate the transaction, and follow the prompts to file a dispute. You then have up to 20 days to either sort it out with the seller, or escalate the dispute to a claim and PayPal will decide on the outcome (the seller will be required to prove they posted the items to you, othewise you should receive a full refund).
If you paid with a credit or debit card, you may be able to initiate a chargeback - you will need to speak to your card provider to see if the transaction is eligible.
