Could not tell you if that happens frequently...was the first time for me and I have have not attempted to buy anything during the game again. I play on the PC and I do know that there were no connection issues .
wrote them on Dec 4/5 and have not received a reply...still 120 gold bars short...also wrote them about the identical problem with Candy Crush Saga ( only missing 10 bars there ) and no reply....
same thing happened to me today after finishing the new levels..so frustrating and it seems like everyone else is getting help with this very same problem but I have not received any reply/support/answer./help......hope you have better luck than I...
actually now it looks like I have received some tools ( hammers ...) I think...not quite sure, but I am sure I did not receive any bars...at least 120 missing my game ID is 1834054665