in fulfillment sales when with a quantity greater than 999 in the transaction to deliver the iVend System does not allow type more than 999 units
By example in a fulfillment sale of 2000 bricks, we can not type 2000 because appear the message "
Compliance amount must be greater than 0"
Need to verify the system display settings : the number decimal and group separator, if it is different from Currency separators , so put this same as below image .