First of I did look at the help page wrt this and it is not helpful.
→ https://help.freeletics.com/hc/en-us/articles/4405638662034-Where-can-I-find-my-payment-receipt-
I made the purchase via the website and I did not get the receipt via email. (I did check my spam folder too).
Anyway I can reach out to the support and request them the receipt.
Hey Suhail 
Yup, if you are missing the payment confirmation please get in touch with us via that page and we can resend this to you 
Hey Ben, thanks for your reply… but I am unsure as to what I should be doing from my side. Can you please let me know which page you mentioned…
I guess he meant the links mentioned in the page you linked in your post.
Hey Suhail, I’ve sent you a PM