Service provider not paid since January

My son was born late December 2014 and soon after was diagnosed with severe jaundice. After being in and out of hospital we opted for home therapy which was authorised by Hosmed. The treatment ended on 18 January 2015 and was submitted almost immediately. Brigitte Williams who provided the service has been struggling to get her payment ever since. She keeps getting told that it will happen at the next pay run. C'mon it's April guys, this service happened in January, how many pay runs must this woman wait for before she gets paid? Someone needs to please investigate the diabolical way claims are being processed.