We're sorry that we haven't made a good enough app for your needs, submit to us any feedback you have so we can be better. We'll continue to improve ourselves to earn back your trust again.
Meanwhile, these steps should help you:
To get a refund
We can't facilitate refunds ourselves through the Microsoft Store due to billing and security reasons.
To request for a refund/cancellation:
1. Sign in to your Microsoft Account that you purchased us with.
2. From the top menu bar, select Payment & billing > Order history (https://account.microsoft.com/billing/orders)
3. Navigate to our app you want to have refunded, and select 'Request a refund.'
For more information, you can check out Microsoft's solution here: https://support.microsoft.com/en-au/help/10558/microsoft-store-returning-items-bought-for-exchange-refund