I would like to hire a Zen Cart Developer to fix minor issues

I built an online store using Zencart almost 10 years ago, and it's not flashy but it has worked well for all that time and I have been able to make changes as needed over the years. However stupidly I decided to let Crazy Domains "fix" it's security and instead they first destroyed the whole store but have gotten it back to a point where customers can place orders but I can't do anything like update product info or orders or even simple things like dates on vouchers, it just sends me back to the landing page without changing anything. Also i am still running version 1.3.9 as I have been too scared to update it as it was all working so well. So if I am going to hire someone to fix the SSL issues then I am best to also get someone to help me update the version safely and fix any errors quickly that happen with the change. At this stage I have demanded that they revert my store back to what it was, so if the person I hire thinks they can fix it and keep the security I will tell them not to go ahead with that. Ideally I would like secure so google chrome stops having a meltdown, and to have it updated to the most recent version of zencart, but primarily I just want my store working ASAP :( Here is the store [login to view URL] and the main site [login to view URL]