Formulary rate but don't pay up to what they say

My Mom is on a heart drug that is the only one in its class. Discovery Health state that they pay up to an amount on their formulary list yet my Mom, who is a pensioner, is having to pay in just over R190.00 on this drug alone, per month because they do not pay up to their quoted formulary rate.<br> When I queried this earlier in the year I was told that's what they pay and the formulary list would be reviewed in April. <br> If you say you pay up to an amount and it even appears on your statements then why have you not been paying up to that amount especially when there is only this one drug on your formulary list and there are no generics available.<br>