I had encountered the same problem that you had encountered. Gentleman Jeremy's Chatot and Socialite Reina's Roselia were both stuck at Level 45. I have finally solved this problem.
You need to have battled and either caught or defeated Heatran in Stark Mountain. This will cause Gentleman Jeremy to have a Level 61 Chatot and Socialite Reina to have a Level 61 Roselia. They will each give you 12,200 Pokémon Dollars. You can receive 24,400 Pokémon Dollars from each of them if you give an Amulet Coin or a Luck Incense to the Pokémon with whom you will be battling them.
I have only discovered this solution by playing Pokémon Platinum since I cannot find any information about it on the internet. This solution should be applicable to Pokémon Diamond, Pearl and Platinum.