Frontline spray is fine for adults, they make the spot on for convenience as some adults arent going to tolerate being sprayed!
Program is a flea contraceptive and doesnt deal with ticks, it stops the flea eggs developing so imo if you have a cat with an allergy to flea bites its not cutting the mustard, the data sheet says it may be necessary to use an insecticide alongside to deal with heavy infestations.
As to other treatments im not sure what else kills them, have you spoken to your vet? Fipronil is the same active ingredient but slightly different recipe so you could try that