Chronic medication

I have been satisfied with the service up till end last year. Most of the time the delivery of our chronic medication is on time. But recently my son's medication (epilim 500mg twice/day)for epilepsy is either out of stock or late. I received 20 tablets short 2 weeks ago(13 th March) It was to follow soon, but up till now nothing. I have phoned 31 March, explained we need the outstanding amount. The pharmasist said she would phone me back,no call received. Today 1 Apr I phoned again, still no reply after being told I will get a call back. Time now 18:31 Tomorrow morning the last tablet will be given. So tomorrow I have to go to the pharmacy again. My son is severely mentally and physically compromised and has constant small episodes of convulsions. I am seriously considering removing our prescriptions from Medipost.