PGWP Extension - An additional fee in the amount of $100.00 is required

[prospectiveab]

I've applied on paper and only paid the 155$ work permit fee, and since I have a permit, I didn't pay the work permit holder fee (100$) as I paid it last year. Now IRCC is asking me to pay the WP holder fee again:

This refers to your application for a Work Permit received 01/18/2023.

An application to change conditions or extend your stay in Canada can only be considered as having been made if it is made on the prescribed forms and if it is accompanied by the required fees and all supporting documents. We cannot take any action in your case for the following reason(s):

[X] You have submitted $155.00 with your application. The correct amount required is $255.00 for the services you requested.

The following documents are required to continue processing your application:

[X] An additional fee in the amount of $100.00 is required. Payments must be made online at www.cic.gc.ca. When you are finished, you must print a receipt of payment and include it with your application. Please send requested items by fax to the following coordinates: ...

Do I fax them a proof of me paying that same fee almost 1 year ago (like a bank statement), or do we really have to pay that fee for extensions as well?

Edit - I've only included 1 proof of me paying the 155$ fee, with a letter that says I am applying for a work-permit extension because a passport renewal.