Pathetic service from Old Mutual when claiming a retirement annuity lumpsum payment

My husband was diagnosed with mm (bone marrow cancer) 5 years ago. He could not earn an income for 5 years. In March 2021 the specialist gave us a heartbreaking prognosis. He has annuities, retirement products and life insurance with Discovery Life, Sanlam, Momentum and Old Mutual. We requested early retirement (due to illness and inability to do his normal day to day job and earn an income) with lumpsum payments. All claims was paid by all other insurance companies, except Old Mutual. Some of them paid within a couple of days. For months the claim was just not attended to no matter how many times we followed up. It is now 5 months and the claim is being send back and forth, because they refuse to pay out the lumpsum. Old Mutual always received all documents and information requested from us on time. Our financial advisor is also trying to assist, but up to now they had no success. The consultant didn't even want to give our financial advisor the contact details of the claims manager? Old Mutual has no customer service - it is beyond pathetic and actually non-existant!!!