alternative to "to whom it may concern" ?

In a blog on my website, I covered just this question. I would actually do a little research and see who exactly your resume and cover letter is being sent to. Call the company (or check out their website) to see who will be doing the interview and hiring process for the position you're applying for and go from there. Once you know the name of the person, address as Dear John Smith. Personalization can go a long way to make your resume and cover letter stand-out from others. Hope this helps!

Maybe try -

ATTN: Hiring Manager for Customer Care Specialist Position

Then follow with a salutation such as Greetings or Good Day or even Dear Hiring Manager

I hope this helps :-)

I would say "Dear Hiring Manager" or "Dear Human Resources Manager"