MSA Payment Issue

Discovery has been paying the shortfall on my diabetic medication claim for over a year with not a single rejection. I claim the shortfall from my MSA and it is paid directly to me. Now all of a sudden the amount is being rejected(R167.21) and nobody can answer why it was always paid before and not now. Clearly Discovery does not know what it is like to be a diabetic because they can't even pay for 150 test strips per month. A type 1 diabetic needs to test 5 times a day. Now they won't even pay for the shortfall from my MSA which belongs to me in any case. Not happy at all! Please Resolve!