Problem in importing data in csv file

Problem in importing data in csv file

I have imported some csv files in Zoho CRM and now after some successful import, I can't even see name of last 6-10 csv files imported in Zoho CRM. This sounds strange to me as I have given enough time to see import history i.e near 5days now and still neither file name nor its status can be seen in import history. I have to import almost 59k Notes using Migrate Data from other CRM option found in Zoho CRM Setup but after importing 6k only, I am facing this problem!
Please suggest