Theme won't load, and when it loads, reverts back to old theme?

I've purchased the Helena Pro theme to update after my first year expired. The new theme won't load through the WordPress site, I've downloaded the zip file and uploaded it several times. It says that the update was complete, then after some time the theme goes back to the previous version and the update never stays. After the first attempt at uploading the new update, the 1.4, content on site disappeared? I have a very important function occurring this evening and Catch Themes makes it impossible to speak with someone to fix something, I've paid for??? I am so brand new to site building and just need some technical assistance or someone to walk me through this. If anyone is looking at this, please call me (775) 750-8181. I am struggling with this...