You get a Tourism Visa from a Thai consulat in your native country.

You are lucky, you get 2 entries.

After 6 months (around) in Thailand, you go to an other consulat in KL, Penang, Vientiane or else to ask for a new Tourism Visa.

What happen if they refuse it ?

Can you still enter Thailand with a Visa Run for 1 month ??? to take your flight back to your home country.

Yes, you can enter on a 30 day entry stamp, and you can do that for a total of 90 days in any six month period.

correct me if i am wrong but the number of days depends on your home country of origin passport

There are (3) separate categories of nations which receive different levels of privileges.

A 30 day visa waiver, a 90 day visa waiver, or only a 15 day visa on-arrival. And the

kinds and approvals of extensions also appear to vary. http://www.mfa.go.th

What happen if they refuse it ?

Can you still enter Thailand with a Visa Run for 1 month ??? to take your flight back to your home country.

Depends very much on your home country ! Where are you from ?

Naka.