Your hosting provider cannot tell you exactly what is the issue since they are not experts for the WordPress CMS so do not believe blindly when hosting support generally point that all issues come from the “Theme”.
There are many things that could affect the theme to become buggy and slow and the primary reason is that many users install more than 20 or even 30 various third-party plugins and all those plugins are including tons of scripts and stylesheets which could make various script or CSS conflicts.
So if you can prove that some bug is theme related you will need to give us required details on how we can reproduce the bug you are writing about and after that, if we confirm that there is really a bug on our side we will prepare proper theme update.
Right now I can see some jQuery errors on your website which are not Fury theme related but as I can see it is related to the Jetpack plugin (EU Cookie Law).
We also do not provide any support for third party plugins you have installed, only if the theme itself has a bug we will give you proper support and theme updates.
Thanks for your understating.