My competition owns the domains of EVERY potential client of mine. Help!?

Quick information on my business and business model:
- I rent websites to certain offline niche/industry. Monthly rent. (professional service firms)
- I essentially just install a wordpress theme in their specific domain, rebrand it to fit their corporate image and then my clients update their own content.

Easy, fast, profitable and scalable model.


I was doing research recently and found my only competitor in my country.
- He follows my same business model, in the same niche, but my websites provide much more value to clients.
- His websites are outdated for 2013 (his websites are not seo-friendly, crowded-design, use flash in certain sections and are not responsive)
- My websites are more clean, responsive, dont use flash and are seo-friendly

I offer a much better product and i have no doubts i can take over this market.

Through google, backlink research and a look at his corporate site I found a huge number of his clients (he listed most of them in there in his portfolio). He pretty much handed me his complete client list, between 300 and 600.

I plan to take over this clients since they already know of the value of this certain type of website and are already paying for a similar solution.

The issue here is that my niche is not tech-savy... I did whoIs searches of my potential client domains and 95% of them "dont own" their domain, my competitor is the legal owner of their corporate/branded domains.

Example: "competitor marketing" services "Martin's Law Firm" and legally owns "Martinslaw.com"

His client list represents $60,000 USD per month, just on website rents (imagine how much you can upsell to this offline firms). Since ill be trying to take over his clients, I believe that my competition is not going to be taking this well and they will probably try to retain the clients by retaining their domains. After all, they legally own them.

So how can i proceed to attack this group of clients and manage to keep their corporate domains? Is there any legal resource I can use with ICAAN in order to transfer the ownership to my clients??