Pharmacy Direct is a ****

Pharmacy Direct is a ****. They shipped 2 months medication to me in advance before my medical aid had processed their payment. During that time, my doctor ran a series of tests which resulted in him changing my medication regimen and prescribing different medication due to medical findings. Now the medical aid only processed one month medication from the previously shipped medication, and proceeded to cover the new prescribed medication. In turn Pharmacy Direct charged me for that medication, I informed them that I did not use the medication and it was not my fault that they shipped 2 months worth of medication. They requested I return the unused sealed medication and that the debt would be cleared under my profile since I did not use the medication. I returned it as instructed, however, they are now threatening to not deliver my next order until the debt is settled. How so? Because the agreement was that since the medication is sealed, I should return it for debt to be cleared. In essence, they have their medication back and still want money for it. That’s ********. Why should I pay for something I didn’t use?