Can you put any package into a drop off slot as long as it fits?

I accidentally put a parcel in a metered mail slot at the PO How long is my delay? The label is pre-paid, 2 to 5 days priority It shouldn

Email* Enter correct Email ID Mobile* Enter correct Mobile Number Model Drop Only Pickup and Drop Only Doorstep Advantage Pickup Address Flat

mail slot insulation It provides you seamless service booking experience with service center locators, pick up options, slot Pick n Drop Pick n Drop is a unique

mail slot sleeve Metal Rustproof Post Box Wall-Mounted Key Locking Premium Mailbox with Top-Loading Letter Slot Drop Box Case · TypeOther · StyleOther · MaterialMetal · Brand Name