Sounds like you already know the answer.
If his business was closed and he re-opened a new business under a different name, odds are he is not reputable, and any more money you provide will just be a waste. You MIGHT get the stone counters you asked for, you might not. And probably they won't be installed properly even if he does finally complete the job.
When I had my home built in 2015, I chose not to get counter tops from the builder because they wanted to charge me way too much. So I shopped around and found a local company in my area who does them. They were nearly $3,000 less expensive. I agreed and paid them a minimal deposit to get started (10% of the total quoted cost). Their guys came out, measured everything with laser precision, and brought the measurements back to their shop and my counters were installed perfectly in the kitchen within a month.
Now that same company also sold me a granite countertop for my basement bathroom, and that we had an issue with. The salesman I dealt with kept delaying me and finally told me that they "lost" the piece of stone that was set aside for my bathroom. When I came out to the company and discussed the issue with the owner, he immediately arranged to cut a new piece for me, no extra charges, despite the fact that the one I originally bought was on sale because it had been precut the wrong size for another house.
Good companies will address problems and delays by making things right for you. They don't give excuses for delays.
I know it's upsetting, but you may do well to cancel your deal with this person (considering you never signed a contract anyway) and give up on trying to get your deposit back. Then go to a place that does have a better reputation. I personally would not want someone I can't trust doing work in my house.