Cannot detect/Take a long time to detect my External Hard Disk

“cannot detect/Take a long time to detect my External Hard Disk On My Laptop WD Mypassport Essential SE 1TB USB 3.0”

Hello there,
I just buy my own portable hard drive a month ago but suddenly yesterday it take a long time to load the Drive about 30 minutes until an  hour, the speed of the drive also has been drop down too 100kb usually it will take less than a minute to transfer 1 gb data with transfer rate 30MB,so i am try to troubleshoot the drive and scan it to search any failure or bad sector but the drive is look fine,so i took it to the store where i buy it and they said it cannot be repair the WD center will just replace it with a new one.i am kinda disspointed wth this product perfomance and their customer service,if there is any way to repair this external would be better than replacing it with a new one…this drive contain my future and my memory.:confounded:

That could be a data corruption problem, just backup all of your files and format the passport.