Preply Closed My Account Without Explaining Why

I have been taking lessons regularly through the Preply app for a long time, and because I have been satisfied with the service, I have also recommended it to many people I know. Under the referral program, when someone I referred subscribed, Preply credited my account with a $30 balance, which I was using to pay for lessons. However, today both my account and the account of the friend I referred were suddenly closed without any warning. My friend's account was closed in the middle of an ongoing lesson, and when I then checked my own account, I discovered that my account had also been blocked.

I am currently unable to access my account. Even though I enter my correct password, I receive an “incorrect password” message and cannot log in. In addition, I had made the payment for my friend's account, and there is approximately $61 remaining in the account. I have also received no information or explanation about why the accounts were closed, and I have not received any notification email. I contacted Preply's support team by email, but I have not received any response so far, and I cannot find any other customer service channel through which I can reach them.

My Preply account is registered under the name Selami K********, and my email address is t*********@hotmail.com. I am requesting a clear and specific explanation as to why my accounts were closed, a refund of the remaining balance, protection of our existing subscriptions and lesson credits, and, if possible, restoration of access to my account.