I just did not played long enough to forget about it.You mean the first 5 Mercenaries? They ran way before you negotiated with Giron so your Mercenaries protect Arenfield?
I understood you start to pay your men after you first asign them to guard Arenfield.
In the Interface in Leader's Tent's, in the lower right corner, it is indicated how much money you have in the chest, how much you must pay your men and how many days are left to deposit the money in the chest.
As soon as i recruited 5 mercs and returned to camp, 2 of them alredy fled from camp.
And you only will know that you have to put money in the camp tent treasury only after you return there after recruitment.
Normally hint about money in the tresuary should be before start recruitment and not after.
Because this way i can't even put them in Arenfield there is need for 4 Mercs and i lost 2 alredy before entering camp.