Hi
I usually consider import time roughly 3times the export (without the deletion, otherwise it's longer) but in your case it looks it's going really slow 
Have source and target same hardware architecture (cpu mem disks) characteristics? (this could make a big difference) Network? I mean is the file phisically on the drive of target system or is somewhere else (sometimes the network between prod and rest of landscape has not good bandwitdth and speed)
What's your db engine? (Check also db space even if this should not be the problem for your import)
Then, the dump. You said there are plenty, can you describe me the frequency. Basically, it could be a job from previous client that is trying to insert records and clashing wiht the import(so there should be a precise frequence) or it's your import
First case, stop the job! Second case, it looks that your import is going on and at the end of the import you'll receive a list of error that you probably will need to fix
Let me know
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