I have bought the lifetime version of plus, but it still shows me to unlock the plus.

The purchase record shows that I have successfully purchased the lifetime version of plus (I bought it in April this year). Recently, I opened the program, but it has been asking me to buy it again. After pressing the purchase button, it also shows that I have paid. Is it free to get it? After agreeing, it still shows that please unlock the plus. I don't know what the situation is like. The money I paid is eaten up like this?