Discovery Vitality rewards becoming more hassle than they are worth

I really love your concept but the execution thereof is becoming beyond frustrating. I use my earned miles to purchase a voucher for exclusive books to by my 9 year old a book that she has been longing for, we drive to the mall on Saturday to get the book with great excitement only to be told at the counter that the Discovery system is offline. I try and make it up to a very disappointed 9yr old by driving back on Sunday and yes you guessed it Discovery vouchers are offline. I then buy a Nespresso voucher to purchase coffee, make my purchase (or so I thought) but a week later realise that my coffee has not been delivered. I call Nespresso who says that the voucher did not go through so they cancelled the order and I need to get a new voucher from Discovery. I call Discovery who tell me that they have been having problems with Nespresso vouchers but they will try to resolve it in the next 5 days. End result: I have no coffee, I do not want to buy coffee as I want to use the voucher that I am hoping to get back otherwise what use is the voucher and I have spent and hour chasing my own tail. Not impressed