Gems taken for previous challenge goal prize but not in my inventory

[AmandaAtLeeds]

I visited a neighbour and box appeared "you have not completed the task in time do you want to buy the prize" challenge was mama mia which I didn't do but liked the prize. I pressed yes, the gems went but I can't find the prize.

I'd like the prize or my gems back

[AnnirasSweets]

I visited a neighbour and box appeared "you have not completed the task in time do you want to buy the prize" challenge was mama mia which I didn't do but liked the prize. I pressed yes, the gems went but I can't find the prize.

I'd like the prize or my gems back

There is a recurring bug (since at least 2016) that sometimes happens where old goals will pop up and ask for gems to finish goals but paying the gems does nothing. Official recommendation is that when this happens, force close your game and reopen it; the pop ups should then go away.

As for your current missing gems, if you open a Support Ticket with s8 they should be able to fix this for you.