Lubad

i go to the old man and ask him for a voucher and then he asks for a ditto so i go to route 8 and spend like 30 minutes getting a ditto and after i finish getting it i went back to the old man and gave him the ditto then he asked for 40k and i had around 20k so i couldnt get the voucher because i originally thought it'd be for free after i get him the ditto, after that i progress and play the game for a while and after i get my money i went back to the old man to give him the 40k and he just asked for a ditto and said they appear in 8 or 13 and check your pokedex for more locations and i dont know if its a bug that i have to give him another ditto if i go and come back but someone told me to report this here, either way im pretty sure the pokeball means i already caught it before and its not in my pc so it must mean the old man took it since i didnt release it either