What is credit Reversal? How that happened? Does it means I lost the money from my balance?

A credit reversal usually occurs when a temporary credit was applied to your account. This may occur when the account owner starts a dispute over a transaction or returns a product or service. The temporary credit may be removed (reversed) when the transaction dispute is settled but not in favor of the account owner.

https://www.goldmansachs.com/terms-and-conditions/Apple-Card-Customer-Agreement.pdf