do you have to have all 3 credit reports?

[adaughter]

so like I took my parents to get their credit reports at experian the in office agency and they had no problem getting a credit report...but when we went to the lawyers office to get the other 3 from transunion and equfax it kept saying unable to match identity and we must do it by mail instead....should we just file with just the one? because it does have the major creditors on there...the lawyer said I should at least try to get the other 2 by phone thoo. I dont know what to do?