Looking for someone I didn't know. Kept insisting I knew the person.

They are a debt collection company. They've been harassing us for a year trying to locate someone with the same last name as ours.

Then you should have sent them a. a certified, return receipt "not me" letter, b. reported them to the proper agencies, and c. sued them for FDCPA and TCPA violations.

Read up on your rights here and also make a complaint at this government site:  http://www.consumerfinance.gov/

Also file a complaint with your State Attorney General's office.
List of State AG’s offices:   http://800notes.com/faq/attorney-general