Empty filed value getting selector issues error in PDF files

i am using get text activity and export to excel
i have more than 5 pdf files .in that Columns Name,Custid,Vat,Duedate, volume…
but some pdf files doesn’t have values like it is like émpty values.in this case selector taking another column values .its getting error

example…Name,Vat value empty .

i am getting selectors issues …how to handle this ?