Disappearing content when saving a page

Hello,

I am currently helping an associate of mine with their resume webpage and on the testimonials section I noticed special characters being implemented in random parts of what was placed. When I went to change the characters out and save, all the content disappears then after.

As a side note this site was previously hacked and I have reinstalled everything already and the error still persists.

Here is a link to the page I am talking about.

http://www.abekarar.com/testimonials-4/

Anyone able to help?