There are two possible reasons for this.
Brand versus generic prices
The price listed on the card is for the generic form of your medication. The pharmacy might be quoting the brand price.
The pharmacy is running a different NDC
Every prescription medication is labeled with a unique NDC. An NDC is a National Drug Code assigned by the FDA (The Food and Drug Administration.)
Our direct deals with pharmacy chains are negotiated based on a specific NDC for a specific medication. Therefore, the prices we list on our savings card are based on the specific NDC of the medication that we have negotiated a price for with the pharmacy.
The pharmacy might not have the medication with the specific NDC that is in our contract with them so they may offer to give you the medication with a different NDC, manufactured by another company, which may result in a higher price.
We can not control this higher price because we do not have a deal with the pharmacy for the specific NDC they were offering you which is why they were charging you the higher price and not the price listed on our savings card.