Many data brokers will not permit third party services to remove the data without a signed limited power of attorney. Note that the power of attorney is limited to interactions for submitting removal requests and opt outs.
Isn't it to be expected? I guess that they have to make demands on your behalf to have your data removed. I guess that's optional because they can still work without it is some cases, and ask you on a case-by-case basis for others, but that's extra work for you and for them, so they may not do it, at least not on the lower tier pricing.
Blame data brokers for making such asinine restrictions.
You can also just use the free version to collect a list of brokers your self and manually contact all of them to find out how much of a pain in the ass it is.