He was like, "What is it in English?" "What do you think you're translating?"
I have asked students and non-native speakers exactly the same questions, when they are using a word in a strange way or simply overusing it.
In my head, o zaman is the perfect expression, and can be used in the following ways:
Tamam o zaman OK then
bla bla blah, o zaman.... bla bla bla, so / therefore / as a result / in that case...
O zaman, senin fikrin nedir? So, what do you think?
O zaman, ne yapacaksın? So, what are you going to do?
The first usage is probably ok. The second one could or should be replaced with o yüzden or böyle or a bunch of other options. The third and fourth are apparently just unnecessary. Drop the o zaman altogether.
But then we get into idiolect, the individual use of a language. In English, I say "so" a lot. More than most people. Especially when I am teaching. "Ok, so..." is an expression that students have actually made fun of me for.
O zaman... at the end of the day, there will of course be some compromise. I will probably continue to use this expression more than most Turkish speakers, and in slightly inappropriate ways, but I'll use it less than I did last week.