I did an online purchase on 28 april on asap my order was processed on ther new app which have so many glitches n issues no order number was generated

I did an online purchase on 28 april on asap my order was processed on ther new app which have so many glitches n issues no order number was generated .than the money went from my account as per now the money still not refunded back to me .i have been up and down with store and email and online calls people promising to get back to me no one does the most horrible exp and service i have ever experienced i want my money back i requested an authorisation letter they such an big company they cudnt even give your a proper letter to get your money back its a nightmare with this *********** people reallly