Profile: finestcommerce

I have checked my nopCommerce (version 4.5) store, which uses Nop Templates  theme Avenue, with Silktide Accessibility Checker and I found some issues related to Ajax Filter plugin.
I have an issue on category page where I use Ajax Filters plugin. When I check category page with Silktide Accessibility Checker then it shows an issue Screen reader links WCAG 2.0 A 4.1.2, which is related to clearFilterOptionsAll (<a class="clearFilterOptionsAll" title="Kustuta kõik" style="display: none;"></a>)
– „This link cannot be selected by a screen reader (there is no text content inside the link, or a href)“.
What is possible to do to make this link accessible for screen reader?
I have also another issue related to the same Ajax Filters plugin. When I try to navigate with keyboard on category page, then I can navigate to filter options only when filter is open. When fiter is closed, then filter is skipped and I can not navigate on filter options. Is this plugin using nonstandard keystrokes or these filters are not keyboard navigable?