He issued a threefold divorce that So and so should not work with him in the store or else he would leave

Praise be to Allah.

If a person swears to divorce his wife with the intention of divorce, then divorce takes place when the oath is broken, according to scholarly consensus. 

If that was done in a moment of anger, then it is subject to further discussion. This has been discussed in the answers to questions no. 96194 and 22034. 

If he swore an oath not intending divorce; rather he wanted to encourage himself or someone else to do something, or to stop himself or someone else from doing something, then this comes under the ruling on oaths and he has to offer kafaarat yameen (expiation for breaking an oath) if the oath is broken, and that does not count as a divorce. 

Secondly: 

Threefold divorce counts as one according to the more correct opinion. See the answer to question no. 96194. 

Based on that, if you intended divorce when you swore this oath, and your anger was not of the kind that prevents it being counted as a divorce, then you issued one divorce if you stayed in the store. But if he left the store or you left, you do not have to do anything. 

People should avoid using divorce inappropriately and adhere to the limits set by Allah, so as to protect their families from breakup. 

And Allah knows best.