Hi writing on behalf of a family member,
She joint universal credit in October 2019 she submitted her first health sick note in November 2019, in February 2020 she filled a health questionnaire out following a health assessment in March 2020 Further on her papers got lost as well as her medical records and health questionnaire. (July 2020 joint partners claim )In September 2020 she came to a decision of only limited capability for work, she  appealed this decision. (Became a single claim as no longer with partner) Her case got heard july 2021 during this she won and got awarded limited capability for work and work related activities. Today she received a letter stating she is only entitled to one months backdated pay.
Have they missed read her dates due to changing form a joint claim back to a single claim and got this wrong or is she only entitled to one month? Thank you