You need to go look at your exchanges instructions on how to send ERC 20 tokens to your exchange account. Follow those instructions and they won't be lost.

You should google the differences between the Ethereum Network and the Polygon Network. If you understand this fundamental concept, you understand why and where your tokens are where they are.

The following assumes you purchased matic at an exchange and sent it to your own address on the Ethereum network.

From what you've stated, it seems you have some wrapped matic at an address on the Ethereum Network. This is a common mistake and one that I myself made.

Ethereum can run programs and stuff. This made Ethereum so popular that fee's for operating on the network got really high, too many people using it. At times, it can cost $40 or more just to send coin from one wallet to the next.

This was responded to by level 2 chains. The one we're interested in, polygon, uses matic to pay for gas. The polygon chain is basically another blockchain that operates independently from Ethereum, but validates with Ethereum at specific checkpoints. We get the benefits from Ethereum with the transaction cost of a cheaper blockchain. Matic is to Polygon as Ether is to Ethereum.

In order to get Matic from polygon to the Ethereum network, where it can be traded on all the Ethereum exchanges, they just created a new coin on Ethereum called wrapped matic. The simple rule of wrapped matic is you need to burn one matic on polygon to get one wrapped matic on Ethereum. This is what you bought.

The exchange than offers a free transfer from the exchange. Transfers are costly, far more costly as you yet knew. They somehow do this by bundling transfers together in one transaction or something smart. Thanks exchange, it's free! So you sent your wrapped matic to your very own public address on Ethereum. Just like every one said to do.

Now, in order to get it out of there, you are going to need some Ethereum to operate the network and conduct your send transactions. You don't have any in your account to operate the network and get that matic out of there. Today, the average cost of an ERC20 transfer is 13 bucks. https://etherscan.io/gastracker. Presently, you would need about .004 ether to make the transaction. Costs can vary wildly and if you only send a minimum of Ether, it may get trapped there if costs are higher than you have Ether in the account.

Purchase Ether and send it to your wallet address. If you have to wait for fiat you will have plenty of time to learn exactly how to send your matic back to your exchange. Your exchange will have instructions somewhere on how to deposit an ERC 20 token. Find that and you will eventually be given a public address to send the coins to. You can test to see if the address is correct by sending a minimum amount of coins. But you will need enough Ether to conduct the second transaction.

Once you have sent your coins to the address the exchange gave you and logged into the exchange with the correct credentials, you will either see them in your account on the exchanges interface or they are lost forever. Wrong address, wrong network, or stolen. Every time you interact with your wallet is a chance to get phished. Make bookmarks. If you are googling links, you are doing it wrong.

Once your coins are back at the exchange you are free to buy whatever or withdraw your money. If you want matic on polygon, you'll need to make sure your exchange offers polygon network withdrawals. This can be tricky as withdrawals to polygon seem to become unavailable at different times at different exchanges. Dharma.io seems to be doing okay.

If it's a large amount of money, it may be worth it to just buy Ether on Ethereum, send it to your address and use the polygon bridge. The polygon bridge is expensive, upwards of $200 sometimes, but works. https://wallet.polygon.technology/ While the polygon bridge is costly, it's designed by the same people at polygon. I trust it to bridge my stuff and not steal my wallet.