Hi Chris,
First of all if there is a basketball size cluster of bees remaining, whoever did the removal did a lousy job. Is it possible that a new swarm moved into the same spot?
If it is not a new swarm and they are just left behind bees, then they will most likely just perish or move to another colony assuming all the comb was removed. If some comb was left behind and there was young brood in it, they could raise a new queen a survive.
You first need to determine if there is comb or if they are building comb.
If there is no comb, they bees can be salvaged by placing them in a hive with a purchased queen. If there is comb, you could cut the comb and put it in a hive and determine if there is a queen laying or not. If there is eggs being laid then a queen is present and your hive is set. If there is no eggs, there is either no queen and a purchased one can be supplied, or there is a virgin queen that has not started to lay yet (this would be the case if they where able to raise a new one from brood left behind).
Please update your profile with your location, perhaps there is a member close to you that could help you out.
rob...