Duplicate, submitted URL not selected as canonical

Question

I have my canonical tag URL as http://www.example.com/ in HTML header and also same in sitemap.xml. my host has enabled SSL and previously in search console I have been added HTTPS version of my address and three green check marks showed and was okay, then because SSL certificate was low quality some mobile phones couldn't reach it and I disabled SSL, but now Google selects HTTPS version of my address. here is web.config

<rules>  
    <rule name="Redirect http://example.com to http://www.example.com HTTP" patternSyntax="ECMAScript" stopProcessing="true">  
        <match url=".*"></match>  
        <conditions>  
            <add input="{HTTP_HOST}" pattern="^example.com$"></add>  
            <add input="{HTTPS}" pattern="off"></add>  
        </conditions>  
        <action type="Redirect" url="http://www.example.com/{R:0}" redirectType="Permanent" appendQueryString="true"></action>  
    </rule>  
</rules>

its HTTPS version address goes to site control panel and certainly isn't same as HTTP version so that it chooses that one. any suggestions?