[Koha] Duplicate marc records and lost records after cataloguing

Hey all,i need some help on this, Our database keeps showing duplicate records some with no itemes and when we try delete that does not work.They are like permanent records here. A new problem has now occured,after catalouging and adding new records on serching these titles the search result is "not found",BUT when issuing the same title,then that works..Looks like our database has lost it. How can we deal with these issues, anyone. With kind regards Mary Maina