Can't collect the reward for completing all daily activities

I'm unable to collect my 10 gems earned by completing all of the required tasks. This same thing happened to me 2 or 3 days ago & once like a month ago. I've talked to other players having the same problem and/or they can't rent a plant bc there's not a plant for them to rent. Pls advise when this will be collected as it seems like I always have problems with your app. Thanks