I worked in a private limited company five years ago for a period of 10 months. I left with a proper resignation and verbally requested an experience letter, but the Operations Head, who handles HR work, denied it at that time. I am now asking via email to provide the same, and the same person has again denied, stating, "It’s not possible to provide any experience letter at this stage (after 5 years). The management has changed, there is nothing I can do." I have taken acknowledgment from that person over email, mentioning the period of work and attached copies of the offer letter and resignation in the email. He/she replied to the email stating, "I can validate your time and exit as per your documents; you can use this email as proof of your service." The person is still the whole and sole head in that company. Will companies like TCS and Accenture accept this email instead of a relieving/experience letter? Will this affect my background check?