Looks like you've got 51 rows of 10 columns there are in the cell array C. I'd say you've got the data "loaded" just fine.
What you are likely looking for is a slight modification and writing
fmt=repmat('%s',1,10);
C = textscan(fid, fmt,'collectoutput',true);
To see the results, try
C{:}
To dereference the content of cell arrays see