I have a license but no credit?
You are probably referring to the plagiarism checker. Plagiarism checks are only included as part of the Premium Plus package, and not the Premium package. This is to keep costs lower for people who do not require plagiarism checking as part of their workflow. If you require plagiarism check, then you can purchase them as ad-hoc packages here: https://prowritingaid.com/en/App/PlagiarismChecker