I am having the same issue. I buy 5 diamonds using 100 energy. I do it 4 times to be able to buy a boost of 100 energy. Then with my total of 200 energy I buy the 5 diamonds and when I try to buy the Limousine it tells me that I don't have enough diamonds and the transaction does not happen. I try by pressing the 60 diamonds directly or selecting the amounts of limousine by pressing the icon. I'm using android 7.1.1, I don't know if There's an emulator that would work better for this.
Thanks for your help