I submitted a request for a stay and the agent was able to find the rate on the submitted website. This particular online travel agent shows in the details for which companies they act on behalf as an agent.
It says for example booking.com, expedia.com or other wholesalers such as WelcomeBeds, Ratehawk and Solole.

The claim was rejected with this reason:
I am unable to approve your claim because you have provided flexible rate XX for comparison that is only available to the following guests:
Provider Ratehawk: company website-must be a member
Our Terms and Conditions state that the comparison rate must be available to the General Public, without restriction.

I am a bit puzzled by this reply. I double checked and I can see Ratehawk is a subsiduary of emerging travel group. They also own zenhotels.com.
The website distinctly differentiates the business of the two brands.
Ratehawk caters to: booking platform for travel industry professionals providing hotels, air tickets, transfers, and other tourist services
Zenhotels caters to: hotel booking website for individual travelers who are looking to find the best rates anywhere in the world
Individuals are not the business of Ratehawk. The online travel agents does not require registration and is available to the public.

Has someone else made a similar experience?