1mg — Cancelling 4 orders in a row without giving any reason

I was regularly buying medicine for my parents from 1mg and service was very good.. Noticed last one month their service getting deterioted after changing their courier agent. They cancelled 4 of my orders (2021 August month)in a row (PO[protected], PO[protected], PO[protected] &PO[protected]).. What the reason for cancellation after promising everyday that shipment is going to be delivered next day every time. Expect a proper clarification.