I bought it, but I haven't received the serial code for weeks. The trial is coming to an end soon, and there's no answer even if I send you an email!
I want to solve this problem quickly..
maybe...
I think I might have entered the wrong mail at the time of purchase.
looking at your email, I’d guess there was a typo 
Can you try via https://paddle.com/contact ?
Thank you for your response.
I'm currently trying to solve the problem in various ways. I couldn't search only the payment history of this application on the 'Paddle.net ' you mentioned, so I also asked 'Paddle.net '. I'll also contact the credit card company in my country.
If there is any other way, please give me some advice.
What do you mean by “payment history only of this application”? Their bot should allow you to lookup your previous orders
On the same day, I also paid for an application called "Popclip". There are clearly two details in my card details.
But in "paddle.net ", there's only a breakdown of "Popclip"
I'm going to ask my credit card company about this cause
I finally solved it!
I received the code safely. Thank you.