Replace Data Source for existing report in PowerBI

Looking for someone who can fix the above problem. I'm getting this problem "Re: Expression Error.: The key didn't match any rows in the table". Do you know how to fix the PowerBI issues. My Last File contain 4000 rows of data and the new one contain 4186. Ideally i like to replace the old data-sets with New data sets. Following steps already taken, but no success. Like, changed the data source from edit query window and hit the refresh button. Email me on msn.cps@gmail.com, if you think you can solve this issues with your fees. Thanks