I must have accumulated approx 2k gold keys in June's Journey but never received reward. What do I..

Keys are earned from Detectives Needed Challenges and is time limited. They do not carry over from one event to the other. To claim the prizes, you must tap on the stopwatch on the left of the screen before it's gone, which will also show you the prizes, your progress, and how to earn the keys (i.e. either from playing scenes or from completing Help Wanted cases or both).