The answer to your question is too difficult to fully explain here.
Under FCRA, a reporting entity needs a permissible purpose. 15 USC 1681b states what is allowed. Collection agencies are allowed to do hard inquiries assuming the are collecting a legitimate debt.
Soft inquiries are credit checks initiated without your consent so the credit agencies do not lower your score fore these. Hard inquiries are initiated when you go to buy something or request credit. Enough of them will lower your score but they will fade away rather quickly.
A hard inquiry is not the only way for a collector to have a negative impact on your credit report. It is my understanding that the hard inquiry will have a relatively small negative impact on your credit score. (The hard inquiry will have less impact than an actual collection item or negative tradeline.)
Do you know what the debt is that the collector is trying to collect? Are you getting other collection activity from the collector?
You may wish to have your situation reviewed by a consumer rights attorney. I suggest you look for one at www.naca.net.
Skaar & Feagle, LLP maintains offices in Marietta (770 427 5600) and Decatur (404 373 1970), Georgia. The information ("the answer") provided above is for general information and educational purposes only. The answer should not be taken as legal advice for any individual case or situation. Posting the question and reviewing the answer does not constitute an attorney-client relationship. My firm will ask you to sign a written contract prior to the commencement of representation in any attorney-client relationship. Please contact 770 427 5600 or 404 373 1970, if you wish to discuss your situation further. Skaar & Feagle, LLP accepts select consumer rights cases. These cases include, but are not limited to, cases of abusive and unlawful collection activity, debt defense, credit reporting of false or obsolete (old) information, high interest lenders (title pawns, payday loans), debt management plans, and fraud or unfair practices in the sale and financing of automobiles.