Trouble Ordering on website

Hello - I just received this message:

"Trouble Ordering on website
Message: Hi - I wanted to place an order today and do it through the website- however- everytime I add to cart it says my cart is empty and I am unable to place the order- please let me know when your website is fixed- Thanks Valerie" I also received a telephone message similar to this a few days ago. Everything seems to work through my computer.

I just disabled jch optimize, still have joomla cdn running and lots of cache. I have been trying to optimize the site. Is this a javascript type problem. Is there anything I should avoid when using hikashop and trying to optimize? Is there any way to turn these systems off when hikashop is visible (It is not on every page) We are still getting some order through ok. I also just went to a JSN Gruve Responsive template. Running joomla2.5.8 & Hikashop 2.

Thank you - I disabled all the above mentioned modules and site is ok. I do have "conservative cache" enabled and hikashop is still ok.

I really would like to exclude hikashop from all cache, just to be safe, but still use cache on the rest of the site. I tried using "jotcache" and their tech people could not make it work correctly (Jot supposedly can exclude modules - I had hikashop selected) but anyway it did not work.

I see some modules in joomla have a way of disabling cache for just the module. You mentioned some "exclusions" - Is there some way to write some code that excludes hikashop from the cache system? (I do not write code by the way - so if you have something, I need to be able to paste it somewhere.) Or use a different template for the page that hikashop is on (I am not liking that idea - but ???) (I do have the checkout in a hidden menu to try to keep extra things from loading)