It could be that you're translating the wrong string in String Translation page. To translate the 'contact' button text, please follow these steps:
-go to WPML > String Translation.
-scroll down to the bottom of the page and click on the link "Translate texts in admin screens »".
-search for 'splite_opts'.
-Under it find 'side-button-text'. Tick the checkbox and click Apply to add it to the String Translation table.
-Now you can go back to WPML > String Translation and you should see the string added there. Translate the string completely and save.