Tot zo .. I thought so

I got an sms from a Mark, my dutch friend from Goirle. He said he'll meet online by 10pm. I sent in a response "Alright, Tot zo". I thought at first Tot zo means see you later. But it was not... when Mark called all of sudden to ask " You didn't mean you want to meet me online after a few minutes because thats what Tot zo means." To my surprise I just have to fix my dutch vocabulary hehe.. and of course I answered back.." Sorry I thought it mean see you later at 10pm".