Custom emails after successful payment from PayPal button
I have a WordPress website(Not using Woo Commerce). I have providing 3 service to the users with different price. In my system, I have created 3 PayPal buttons with 3 different prices. The payment is working fine. Now I want to send email to the customers those who paid me. 3 Services have 3 different email content . How can I achieve this? Can any one please help me to do this.