Why didn't Wolfshiem come to see Gatsby when Nick sent for him?

Wolfshiem didn't come when Nick called because he was tied up with important business.

Dear Mr. Carraway. This has been one of the most terrible shocks of my life to me I hardly can believe it that it is true at all. Such a mad act as that man did should make us all think. I cannot come down now as I am tied up in some very important business and cannot get mixed up in this thing now. If there is anything I can do a little later let me know in a letter by Edgar. I hardly know where I am when I hear about a thing like this and am completely knocked down and out.

Yours truly Meyer Wolfshiem