Urgent application refused

Hi I am writing on the behalf of my friend. Her application was refused yesterday on the basis of her private life 20 year long residence in the Uk. She's been living in the uk for 21 years and 4 months however home office requested for more information regarding her residency she was unable to provide letters for the pass 20 years,however whatever she had in her name. In the refusal email she met the suitability but eligibility they said she didnt qualify as she fail to submit evidence of the pass 20 year. she submit it in the morning yesterday. At 3pm in the afternoon yesterday home office sent a refusal email with right to appeal.

What can she do to prove the 20 year residence to the appeal court she is worried sick and I feel so bad for. her.

I'm very much hoping you're not acting in a capacity of immigration advisor, getting paid for your services, while seeking advice on public forums.

What exactly does the letter say?