MoboReader €79.61 Charged by Chang Technol: Purchases Not Recognized

Since I subscribed to the MoboReader application on my Android phone, several debits have been made from my bank account in favour of “Chang Technol” instead of Google, for a total of 79.61 euros. These payments correspond in particular to the following transactions: on 14/09 one debit of 17.35 euros, on 15/09 another debit of 17.35 euros, then on 18/09 a debit of 21.83 euros, on 19/09 a second debit of 21.83 euros, and on 20/09 a new debit linked to the same reference. Despite these repeated payments, I still cannot finish reading my book on MoboReader and my previous purchases are not correctly taken into account in the application. I am also regularly asked to watch advertisements even though I have already paid. When I try to access “my orders” via Chang Technol, I cannot log in, which prevents me from managing or checking my purchases. I request that my purchases be properly recognized so that I can read the book in full without additional constraints, and that my access to the content I have paid for be restored under normal conditions. If this is not possible, I ask for a refund of the amounts debited, including the payments made to Chang Technol that do not correspond to the proper use of the service.