*****ing payment

I went to collect my pre packed medication and I was given the incorrect medication and I suffer from high blood pressure, the problem was that I could not go back to rectify this due to work, I was called today to get asked about the medication I explained that they made an error and I have the other person's medication I was told I am due to pay for the levi as I did not pay that as I only paid for the over the counter medication, they then sent a driver with a merchant so that the payment is made for the levi, but then I was charged again for the over the counter medication...so I was charged twice for the medication, they are *****ing from me.