Most appliances can be wired for either the 3 plug or the 4 plug. The only difference is that neutral and ground are together in one of the prongs for the 3, and separated for the 4. Part of the difference is the wire and integrated plug at the end of the wire that is connected to the machine needs to be matched to the outlet you have.
First I would check to see if the double circuit breaker is turned on. Sometimes it looks like it is on but is is not. So, one at a time, turn off each double circuit breaker and then turn them all back on. If this doesn't work then either he needs to come back out and put in a new cord that has three prongs on it to plug into the other, hopefully working outlet -- or have an electrician come out to make sure that there is actually power going to either of the two outlets there then if only one of them works.
It could be that you only have one breaker that supplies power to where the dryer is, and the wires need to be switched over inside of the circuit panel box from the 3-prong wire set to the 4-prong wire set by an electrician.