What to do if the serial number of my adapter and charger doesn’t match?

They don't have to match as they are not sold in "matched" pairs. That is, you can purchase these items separately.

If you purchase a bundled set that includes both a power adapter and a charging cable, it's common for each component to have its own distinct serial number. Also, the serial numbers on the packaging may not match those on the individual items inside. This discrepancy is normal and generally does not indicate any issue with authenticity.

However, if you are not purchasing these either directly from Apple or an Apple Authorized Reseller, they could be fakes.

Keep them or return them. It's totally up to you. I have already provided you the answer that these serial numbers will not match. If you keep asking the same question, you will get the same answer.

The device that you use to charge an Apple iPhone, iPad, or Mac is called a power adapter. Sometimes it is referred to as a "charger."

Which exact device do you have and what is it designed to charge?

Ref:

• Power adapters for iPhone - Apple Support
• Power adapter and charge cable for iPad - Apple Support
• Identify your Mac power adapter - Apple Support

Doesnt match with what?