poor service and negligence of customers

I wanted to buy a samsung galaxy grand pro from Zasttra...when I was about to purchase, I so that they have an option for wallet which you can put it money to make the purchase and exchange of the item you looking for easy but then moments later, I decided that I would like a refund from the wallet because they don't give a discount when you purchasing from the wallet. I have been trying to contact them via: email, website chat and telephonically but I get no response in either of these communication channels. I am very disappointed with them. The only reason I trusted them was because I purchased something in 2015 and it was delivered the next day but what I am getting now is just poor service and negligence of customers from them. I kept holding twice on the phone for over 18 minutes and each time it becomes silent and then a voice say "thank you, good bye".