You raise several discrete issues in your question, which I will answer separately.
Your credit report is an imperfect snapshot of your credit history that is 60-90 days old. A credit report is not a legal document, in so much that creditors are not required to report their actions or rights to collect a debt to the credit reporting agencies. A creditor can have a valid debt that never appears on any credit report. Therefore, it is of no legal consequence that a debt fails to appear on a credit report.
Generally, government-administered benefits such as state pensions and Social Security cannot be garnished by a judgment. Private pensions enjoy similar status in most states. However, if you deposit those benefits into a bank account and then co-mingle the funds with money from other, non-exempt sources, proving the exempt status of the funds may be difficult.
Create an account into which you deposit all of your exempt funds, and maintain another account for any non-exempt funds you may receive (gifts from friends, income from work, etc.). Notify your bank or credit union the funds being deposited into the exempt account should not be levied upon, and that the bank or credit union should refuse any levy orders it receives. The bank or credit union may not be able to guarantee that a levy or garnishment will not be placed on your exempt funds, but taking these steps should offer you at least some level of protection.
If a creditor places a levy or garnishment on a bank account containing exempt funds, you will likely need to file a notice of exemption with the court, and attend a hearing to request that the funds be released back to you. If the court determines the funds are exempt from attachment, it should release the money to you.
Keep in mind a creditor generally cannot attempt to levy your accounts until it obtains a judgment against you, so you should have time to take the steps mentioned to protect yourself.
Here, however, you mentioned you received no summons to appear, and no notice of the garnishment or levy order. This may be significant, because in all states the civil procedure laws are such that the defendant is supposed to receive adequate notice of the summons and any judgment. These laws are so important that a plaintiff failing to follow these rules may be subject to sanction and suffer a reversal of the judgment. Therefore, I urge you to consult with an attorney in your state, who will review your documents in person, and can advise you if the judgment can be vacated.
Regarding your immediate concern regarding the levy or garnishment, you must take action quickly. You mentioned you reside in California. In California, the debtor must be notified with an Original Writ of Execution (form EJ-130). See the California Courts Self-Help Center to find the Claim of Exemption form (form WG-006) or Exemptions From the Enforcement of Judgments (form EJ-155) you should consider completing in your response to the judgment. Consult with an attorney in California, who will either complete the correct form for you, or advise you on how to complete the form yourself.
I hope this information helps you Find. Learn & Save.