According to the Lifesum's Terms & Conditions available here, you have 14 days (from the date you receive the confirmation of your subscription via email) to withdraw from the contract with Lifesum. If you consent to have access to the Lifesum services during the withdrawal period, you no longer have the right of withdrawal. To receive your refund, you must send an email to email@example.com.
All payments handled by iTunes, such as in-app purchases, can be refunded and approved only by Apple. To receive a refund from Apple you need to contact iTunes Support within 14 days from the purchase date. To contact them, please follow this link: iTunes Support. You should receive a confirmation email from iTunes Support when they receive your request. You'll receive a followup response with Apple's decision on a refund within a short period of time.
Here you can find a useful step by step tutorial on how to request a refund for an iTunes or App Store purchase.
If you bought the Premium membership via PayPal, please tell us the email connected to your PayPal account, and which payment you would like us to refund you. Best is to send us the transaction number.
If you bought the Premium membership via GooglePlay, please send us the transaction number of the payment you wish to receive a refund for. You find this number in the email you received after your purchase or in Google Wallet. Once we receive this information we’ll be able to issue the refund.
If you bought the Premium membership with credit card, please contact us via firstname.lastname@example.org and let us know which account you have bought gold with.