2019 15" Macbook Pro with sticky keyboard but Apple said that my unit serial number isn't included in the repair program

Perhaps not. Almost anyone whose Mac portable computer has or had this issue

if not serviced by Apple Keyboard Service Program, before these details force an

expiry; by conditional limits as stated in the article, announced to Global regions..

Whether or not each global region had tiny details to include or exempt them,

under some different set of rules, is not visible in this presentation by Region

and with differences in Language accorded to their Locality.

If your region or country has specific language used to show an exemption

locally deployed to support some extension of this, then whoever discussed

this matter from your region, should have worked within your local adjustment.

Your link was from NZ (new zealand) used to bring you here. Most of these

include similar wording. US/Canada-regional article has no country codings

Keyboard Service Program for MacBook, MacBook Air, and MacBook Pro - Apple Support

//support.apple.com/keyboard-service-program-for-mac-notebooks

..Then one could expect no further action would be taken by anyone, let alone

Apple in this matter. The article ends with a statement of fact, which I will post

here for you to read. Dates are a part of the detail that may void this altogether.

Additional Information

"This worldwide Apple program does not extend the

standard warranty coverage of your Mac notebook.

If you believe your Mac notebook was affected by

this issue ~ and you paid to have your keyboard

repaired, you can contact Apple about a refund."

"The program covers eligible MacBook, MacBook Air, and MacBook

Pro models for 4 years after the first retail sale of the unit."

+=+=+=+=+

Contact Apple Legal, if hardware questions involve a depth of context that may include

exemption or inclusion, of facts not in evidence, from this official Apple announcement.

'Apple Products and Consumer Law Rights' (This details regions of Apple's interest.)

[Another angle to resolve the keyboard issue, might be repair by replacement

of the affected key caps and switch mechanisms involved; resellers of those

parts (this link to US supplier) of original replacement parts w/ instructions..

https://www.laptopkeyreplacements.com/macbook-pro/ and could be useful.]

As this discussions forum is not representative of Apple Inc. We're 'end-user to end-user'

of their products; Apple is not here. Contact Apple Legal direct & ask if other factors apply.

(this post is subject to edit)