Using Terra Green Icons in Featured Text Sections

Hello,

Below is the code for my Big Icon Featured Text Section. You can take a look at my site at the link below.
http://prodsvr.com/jobs/aps/

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[row_container dark="no"]

[heading centered="yes"]Featured Services[/heading]

[/row_container]

[row_container dark="no"]

[column width="four" position="first" ][feat_text title="Credit Card Processing" icon="screen" href=""]Terra is a clean and modern design WordPress theme characteristic for its responsive design.[/feat_text][/column]

[column width="four" position="" ][feat_text title="ACH Processing" icon="cog" href=""]Terra features plenty of options for customization in the admin that are easy to use and manage.[/feat_text][/column]

[column width="four" position="" ][feat_text title="Purchasing Card Processing" icon="bulb" href=""]Terra WordPress theme ships with plenty of shortcodes that make content creation a breeze.[/feat_text][/column]

[column width="four" position="last" ][feat_text title="Real Time Check Verification" icon="help" href=""]BlueOwlCreative provides a 5-star support to all clients that purchased our awesome theme.[/feat_text][/column]

[/row_container]

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I need to change the icons. I would like to use the icons that are shown in the link below for the Terra Green theme.
http://blueowlcreative.com/wp/terra/green/icons/

I have tried the versions below to change the icons in my home page shortcode, but it doesnt work.

icon=”icon icon-credit” – does not work.

icon=”icon-credit” – does not work.

icon=”screen” – works but I do not want to use the Big icons only. I need the credit card image.

Pls suggest a fix.

Thanks.