An accreditation body accredits a certification body for specific standards and specific economic sectors, and lists both in a scope document. So a body accredited for ISO 9001 in trade and distribution cannot issue you an accredited certificate for a construction business. A certificate issued outside scope carries no accreditation at all.
Three checks take about five minutes. First, ask which accreditation body accredits them, and for which standard. Press for a named body: 'internationally accredited' on a website tells you nothing. Second, find that certification body in the accreditation body's own directory, which every IAF member publishes. Third, read the scope and confirm that your standard and your sector both appear.
The second check catches the most problems. There are organizations selling ISO certificates that are accredited by bodies which are not IAF members, which means the certificate carries no international recognition and will not satisfy a tender that asks for accredited certification.
We publish our accreditations, the standards each one covers, and the sectors in scope. Where we are not accredited for what you need, we say so at quotation stage and decline the work. An out-of-scope certificate would put every other certificate we have issued at risk.