Today I swapped in the Metamask webapplication 30.512 MDX to XLM. The price of MDX was 1.85 and of XLM 0.39. After swapping I got only 0.0000000493 XLM (BSC network). The fees are not that high, is it? And if Metamask is not suited for XLM, can I still get my XLM (According to BSCscan the transaction was a succes). Where are my XLM now?
Who can explain it to me?

Sadly XLM is not supported by Metamask directly so is probably you tried to get a wrapped coin in BSC. If you like extension wallets you can use xBull Wallet (I created the wallet).

Now, about your XLMs you will need to check is you have a coin in your wallet that says something related to XLM and check the site of the issuer of the coin to know learn how to send that coin to the real Stellar Network