OK a few comments:

1. No one steals keywords. Their is no such thing.

2. Sure people can and do steal content all of the time, but if yours is original and you have the appropriate amount of backlinks then you will out-rank any content stealers with ease.

3. Sure their probably is unethical ways to rank, but their are no set "SEO rules". However I do understand what you saying. If you feel they have copied your content have you filled out the DMCA reports?

4. Lastly I am sure you understand your in a heavy spammer rich niche with printer cartridges right? Backlinks are very important when trying to rank in Google and especially in this industry.

Have you considered some solid Link Baiting and Social Media Optimization for your website?

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