Going mad, strong vs original shortcode

Hi,

I must be missing something or am just being plain stupid but no matter what I try I can’t get the whole text of a testimonial to show if I use the strong shortcodes, but I can if I use the original.

One the page linked to below I’ve used…

`
[strong]

[strong class=”beach,tabbed”]

[wpmtst-all]

Not sure what I am doing wrong, so any pointers greatfully appreciated.,
If you have a look at you’ll see the product of…

https://wordpress.org/plugins/strong-testimonials/