I lost the certificate. Can I get another copy?

Almost always yes. The company that performed the work keeps its own copy, usually for years, because they need it for their own liability. A report reissued from their records is the same document, and most will send it the same day if you ask correctly.

Ask for the right thing

Call or email the company that did the work and ask for the service report or certificate, not "a letter". A letter saying you are a customer in good standing proves nothing to an inspector. What you want is the original document, which names the servicing company, the person who performed the work, the date, and what was done.

Give them, in one message:

1. The service address, not the billing address or the company name.
2. The approximate date, or the range you need. "Everything in the last two years" is a normal request and easier for them than one specific visit.
3. An email address to send it to. Ask for a PDF. A photograph of a tag is not a report.

Companies that service restaurants field this request constantly. It is not an imposition and it does not reflect badly on you.

If the vendor has gone out of business

Try, in order: whoever bought their customer list, since these businesses are routinely acquired and records go with them; your own accounts payable, since an invoice describing the work performed and its date is weaker than the report but is contemporaneous evidence that it happened; and your insurance broker, who may have collected certificates at renewal.

If none of that produces anything, say so plainly to your inspector rather than presenting an invoice as though it were a report. Which is the subject of a separate page on what to do when you genuinely cannot produce something.

If the work was never actually done

Sometimes the search ends with the discovery that there is no record because there was no service. Book it now, before you go back to the inspector, so that the conversation is about a gap you have already closed. Do not backdate anything and do not ask a vendor to. A falsified compliance record is a materially worse problem than a missed cleaning, it is the kind of problem that voids an insurance claim, and it is trivially caught because the vendor's own records will not match.

Then stop it happening again

This request is nearly always made by someone who has the document somewhere. It was emailed to a manager who has since left, or it is in a personal inbox, or it was handed over on paper at the back door during a lunch rush. The document was never lost so much as never collected anywhere in particular.

The fix is to have one destination that is not a person. Whatever you use, the test is whether someone who joined last week can produce two years of reports for one location without asking anyone where they are kept.