It seems that Certificates from that particular college do indicate some kind of achievement, albeit lower than an Associate's degree.
https://www.mdc.edu/academics/programs/certificate.aspx
These College Credit programs are certified by the Florida Department of Education and require fewer credits than an Associate in Science degree. College credits granted in these programs will apply toward the related Associate in Science degree. Students receive an institutional College Credit Certificate upon completion and the program’s title is added to the student’s transcript.
However, if you didn't mean this Certificate, the one Boz linked to,
https://www.mdc.edu/sales-customer-management/
then what certificate was it,
because I didn't notice one for "Customer Service."
But Boz is right - saying I am "a College Graduate" is quite different from some certificate that isn't even an A.A. or A.S. degree....