I have a computer where almost 100% of files in a ton of folders are infected with Zepto virus.
Kaspersky technician told me that they did not have any tool that restore these infected files.
Is there a software tool that I can buy in the market place?
Based on a quick search online, there isn't an unlocker for this. That's not surprising as basic goal of encryption is to make files unreadable by anyone that doesn't have the key.
The standard solutions are:
1) restore from backup
2) pay the ransom
3) recognize that your files are gone
Of course, restoring from backup is your best approach. I'm assuming that this isn't possible or you'd not be posting your question here.
In general, it does sound as if the thieves will restore your files if you pay the ransom. I always discourage this for many reasons. You don't really know if they'll restore your files. Even if they do, you are helping to support their actions by giving them money.
With most of these viruses, removing the actual virus is fairly straightforward. Anti-virus and anti-malware software will usually do the trick. That keeps it from causing more harm but doesn't help you with the encrypted files.