Q: Is Premier Tech Support a scam or legitimate?

Hi Paul, there are a couple of ways to report fraud to the BBB or other consumer protection agency, and yes I suggest that you do so.

Those agencies are at the bottom of this User Tip: Effective defenses against malware and other threats and are as follows:

US Federal Trade Commission: http://www.consumer.ftc.gov/articles/0346-tech-support-scams

Better Business Bureau: http://www.bbb.org/blog/2013/01/new-twist-on-scam-tech-support-calls-installs-vi ruses-on-victims-computers/

The only caveat is that I disagree with one of their recommended actions, which is to "download legitimate security software and scan your computer." Downloading anything, regardless of the source, in response to this type of scam is inappropriate and is likely to result in other, unrelated problems. Don't do that.

I cannot find their physical address nor  their website.

The reason is that they may have none. All a criminal needs to commit this fraud is a phone and a computer, both of which might have been rented by the hour, and could be at the bottom of a river by now. You really have no way of confirming whether the company you called was even "Premier Tech Support", whether that is in fact a company or any incorporated entity existing in the United States, whether it was someone on the other side of the globe fraudulently claiming an association with them, or anyone else, legitimate or not.

The only fact possible for you to determine and assert it is an act of fraud, based on the obviously fraudulent information accompanying the phone number. That is the basis on which to dispute the credit card charge.