White-label services are common.
There is nothing automatically wrong with an agency selling work produced by another company.
That is how a lot of professional services operate.
The problem comes when the markup becomes enormous and the client has no idea what they are actually buying.
Ask who is doing the work.
Ask what platform is being used.
Ask who owns the website, account, data, domain and customer records.
Ask whether you can export your information if you leave.
Ask what happens when something breaks.
Ask whether the person selling the service can explain how it works without calling somebody else.
You are allowed to know whether you are paying for development, management, resale, consulting—or all four.
Middlemen can create value.
But you should know where the value is coming from.