Wrong display of Bottom 3 Text on Mobile devices

On our Website, we want to implement the Phone numer and facsimile in the module position: Bottom 3.
From a desktop view, everything works fine. When the page is viewed from a mobile device however, the numbers vanish and can't bee seen.
https://website.sb-com.de/

Hello,

Make sure that the telephone numbers are linked, with the link href set to "tel:+1-555-555-5555" (change with your phone number). You can add the link using the Sparky Page Builder: www.hotjoomlatemplates.com/sparky-page-b...ion/blocks/paragraph

The HTML source should be:

Now edit the file /media/templates/site/galatea/css/custom.css and at the top of the file, add this:

Regards,
Milos