Lufthansa: Lack of client care and service

On 22 July 2018 we informed Lufthansa that their flight from Brussels to Frankfurt and Johannesburg on 19 July was cancelled and we flew with Brussels Air from Brussels to Rome and with Ethiopian Air from Rome to Addis Abeba and Johannesburg. We booked Economy Comfort but flew Economy class with Ethiopian Air. We requested a refund. Lufthansa reacted on 30 July when Pablo Navarro Ruiz informed us that regarding the incidence of the downgrade in the leg between Frankfurt and Johannesburg the requirement had been forwarded to their department of refunds. It promised that the colleagues will contact us again in the next weeks and inform us about the decision adopted. More than two weeks later and the colleagues did not contact us. The question is, how long does it take Lufthansa to determine the difference and pay out the money? It is now six weeks after flying and Lufthansa has responded with only one email to our repeated inquiries. I would not recommend my colleagues to use an airlines that cannot provide consistent client care and service. At this stage, they do not provide ANY client care!