Lets put it this way, i trained my dogs using treats, praise and toys. They all have good recall. I met a middle aged lab the other day wearingone of these collars and he had the most atrocious recall i have ever seen. He followed up for miles whilst his owner was trying to call him back. Eventually he had to come and fetch him. Doesn't that say soemthing about which is the best way to train?
Anyway i agree that it is best to retrain the recall using another word, starting off with very small dsistances, like in the house and garden. You may also want to introduce a whistle as another signal if words don't have the instant effect.