I want to register a small work from home business and do yearly audits. I have found a tax consultant and we exchanged more than dozen emails. After I asked him about where he got his certification and did specialization, he told me that he cannot help on such level. I told him that I don't need anything special and he questioned why I would need all these details.
Maybe I am too picky here but I just want to be sure I am in reliable hands. He works in an office with several other accountants.
Should I be suspicious here or not worry too much since I will manage the financials on my own? How should I go about finding a legitimate accountant for my small business? How can I verify the credentials of an accountant?
You are right to be suspicious. You have the right to interview an accountant (or any other professional) before engaging in a business relationship. Asking about certifications is perfectly reasonable, and I can't think of a reason why he would be so defensive about it, unless he is trying to hide something.
My advice is to walk away and find another accountant. The best way is to ask those you know if they have any recommendations.
Also see this question, you might find it useful: What questions should I ask when interviewing a potential accountant?
You need a recommendation from someone. Use whatever networks you have to get one. Even a recommendation from a friend of a friend is better than going blind.
If you post your location, maybe someone here will give you one.
In the USA I would ask about recommendations, certifications, experience with companies similar to yours. I would also check a state board of accountancy to see if there were any issues with this accountant in the past. I would also look at his/her prices, but I would not go after the cheapest one I can find because in this industry you do get what you paid for. Better be in hands of an experienced professional who will cover all your bases than to save a little now and then go and spend 10 times more to fix messed up records / taxes.
I, however, noted that you are in Israel. I am not sure about how that works there, but I would imagine you can ask the same question. If the guy is legit, why would he not disclosure his certification, etc.?
And when you say "year-end audit" do you just want him to review your bookkeeping and prepare the tax return? If so, I would not call it an audit. It's tax return preparation. An audit if when an accountant obtains reasonable assurance that your financial statements are free from material misstatements. In the USA an audit usually costs more and is only normally required if you need to provide your financial statements to a bank, another lender or you have public debt or equity.
Finally, 20 emails seems a little over the board. I would just give him a call or ask him to call you. I would call you back if I am an accountant interested in new clients.