Modify existing prestashop module -

I have a multiscraper module that adds products from amazon on prestashop and checks quantities but amazon has updated the site and now the quantities change, I need that when the product ends on amazon it must set the quantity in my shop at 0, and this function is already available on the module but does not work in some casesfor example when it indicates on amazon "Currently not available." the module works and brings me the quantity to 0 on prestashop, instead if there are new amazon words for example "Not available." or "Generally shipped within 1-2 months." this does not go to 0 ,for a programmer it will certainly be simple as the module is already developed and only simple changes are needed.