Myflowerapp — Did not delivered the order

I ordered a cake in this app and did pre payment through online payment and the order was confirmed by the app but in the last moment I received a mail stating order cancelled. When I spoke with customer supporters they were least concerned about the issue and told they will either transfer my money to app wallet or will transfer only 80% of the payment to my account. Such a worst app I have ever used and their intention was to cheat people in the name of app