how can I figure out if my SEO company are doing black hat technique for my website?

I am changing my seo company , the new company is telling me my old company was using black hat technique ( like shadow domaining) , how may I realize if they were using black hat technique for my seo?
Thanks

Hi Ari:

I would suggest having someone take a look at your current SEO campaign, and explain to you the reasons for why or why not your SEO company is using blackhat techniques. The trick is though, to find someone to do this that is not trying to sell your SEO as a result.

I kind of look at this as taking your car to the local mechanic. If you’re not a car expert, that mechanic can tell you anything he wants about what may or may not be wrong with your car. You need a trusted 3rd party source to verify such conclusions.

If you’d like, submit your site for review on sem-tv.com. It’s a new site I put together and I’d really like to do an episode on identifying blackhat SEO techniques. Don’t worry I won’t try to upsell you on anything! :)

Hope this help. Cheers,

Marc