SSH/ Iphonebrowser(google urself) to ur iphone..
navigate to /var/lib/cydia/
delete the metadata.plist...(this will remove all ur added source inside cydia and reset them to original one, so please kindly add back ur source after that)..
and delete this files too..
/etc/apt/sources.list.d/cydia.list
finally, delete anything inside
/var/lib/dpkg/updates/ (dont delete the folder)
reboot ur iphone and open cydia.. u are done.. u got a fresh new cydia..