Double standards

I bought a 2tb seagate hardrive at game promenade in feb 2018 and took it back in april due to it being faulty. I lost sensitive info and documentation as i was told these devices do not get sent for repairs. The store manager explained this to me and agreed to give me two 1tb devices and said if theres any problems i should come in to the store again. I returned one of the drives today cause the input for the cable shifts when trying to insert the cable. Now i was told that the device must be booked in and it takes 21 days to get feedback. Im even being told that the pin is due to customer negligence without even giving me a chance to explain what was wrong with the device. So can someone pls call me to explain this procedure. When i wanted the previous one repaired i was told it doesnt get sent for repairs but now this time around it does? Pls explain to me the warranty and guarentee on seagate devices.