The sample acknowledgement letters for receipt of payment provided below can be used as format templates for official and personal purposes. This letter is to inform you and gain your acknowledgement about the outstanding balance due with Orange Mobile Botswana.What do you need to include in your donation acknowledgment letter? The certificate of acknowledgment (PDF) must be in the form set forth in California Civil Code section 1189. Sample Donor Acknowledgement Letter for Cash Donation. Express gratitude in a heartfelt way. Send a note using Canva's free and customizable thank you letter samples.