Sounds as if you might be a victim of a somewhat dirty trick that many unethical SEO guys do these days. Real SEO work doesn’t go away when you stop performing work, it usually continues to benefit your website for years into the future.
Instead of performing SEO work to benefit your website, he may have been building links to his own website and then redirecting the traffic to yours. In that scenario, you are not paying for SEO work to promote your website. Instead, you are renting traffic from that SEO guy’s website and he’s using your fees to build up traffic to his own a website.
It’s unethical, in my opinion, if he does not disclose the fact he is only renting you the traffic, especially if you hired him to perform SEO for your website. That amounts to fraud, but you don’t have a realistic legal remedy because he’s based in India, and presumably, you are not.
Of course, there are other dirty tricks that he might have pulled, like using the disavow tool to disavow the links he built or requesting that your website be de-indexed via the Google Search Console. In effect sabotaging your website.
The first thing you need to do is check to see if your website is still indexed in Google. Just search in Google using the following search string: site:YourDomain.com
(replace YourDomain.com with your actual website name)
Next, head on over to Google Webmaster Tools and take ownership of your website property so that the guy you fired can do no more harm. You can also gain insight as to what may have happed by looking over the data in the Search Console in Webmaster Tools.