AIG delaying and not paying what is due

My Partner Riva Mary Hartl has had a policy (Hospital Cash Back) with AIG for the past 10 years and has paid her premiums regularly and on time throughout. In July 2019 she was diagnosed with cancer of the stomach and was hospitalised on 1st August 2019 for two days and was then allowed to go home as the surgeon could only perform the Gastrectomy (partial removal of the stomach) on Monday 5th August, She was readmitted on the Monday and the gastrectomy was performed. She was in hospital until the 12th August 2019 (8 days in total) She then had to recover and was sent to an Oncologist who she saw September and was placed on a Chemo Therapy program which started on the 25th October 2019. After the first treatment the oncologist app**** for her to have a Port installed and for this she was hospitalised on the 11th and 12th of November. After the second bout of Chemotherapy she was rushed to the Emergency room with severe chest pains and was admitted to hospital from the emergency room on the 17th November. Various tests were done and it was discovered that she had clots on the lungs and was admitted directly to High Care. She was discharged on the 22nd November 2019. After the Chemo on the 6th Dec she got progressively sicker and again was rushed to the emergency room on the 14th December. She was found to be in a critical condition and was again admitted to Intensive care in an isolation ward. She had to have a number of blood transfusions and other treatments to stabilise her.She was discharged on the 23rd December 2019 after this bout. Her blood count was still very low and on the 6th January 2020 she was readmitted for further blood transfusions and was placed in an isolation ward during this stay in hospital. She was discharged on the 11th January 2020. We submitted claims to AIG for each admittance supplying the original diagnosis and pathology reports and hospital accounts which show the time and date of each admission and discharge. AIG have come back to us to say that we have to supply the following information: 1. Letter of motivation from the treating doctor in each case 2 Pathology reports (original one provided) 3 All radiology reports (CT scans, MRI, x-ray, ultrasounds etc 4 Complete hospital file with Nurses and Doctors daily ward round notes, vital signs, prescription charts, physiothe****** notes etc 5 Bank statements despite that they have been deducting installments every month for the past 10 years. This is almost impossible to obtain and we believe is purely a delaying tactic to try and get out of paying what the policy was taken out for.l We have, we believe, supp**** ample proof of hospitalistions and feel extremely let down by this organisation.