Hello

I purchased a layerslide licence yesterday, but now my website is really messed up. As you see from the picture, the menu on the top is gone, both side panels are gone, and it looks just small and cut off.

I got this error message:

Error Details
=============
An error of type E_ERROR was caused in line 255 of the file /home/eglisesv/public_html/wp-content/themes/betheme/functions/theme-head.php. Error message: Uncaught Error: Call to undefined function wp_get_script_tag() in /home/eglisesv/public_html/wp-content/themes/betheme/functions/theme-head.php:255
Stack trace:
#0 /home/eglisesv/public_html/wp-includes/class-wp-hook.php(286): mfn_defer_scripts('apply_filters('

Please advise on what to do.

Thank you