Thank you for supporting Tower of Saviors! Your inquiry about not being able to collect diamonds paid is well noted.
Please take the following steps with the same device which you made the transaction (the same payment account in the same device):
Quit the game and restart login
Go to "Store" -> then "Diamond Store".
Choose "Retrieve Transaction"
If the transaction was successful, the diamonds purchased will be received and the total number of transactions will be displayed.
If you have further inquiry, please do not hesitate to contact me. Thank you!