MetLife decided I was no longer disabled 6 weeks into my 13 week plan

I signed up for a 13 week plan with Metlife for Short Term Disability. I went on maternity leave. I was given 5 weeks of benefits (due to the 1 week waiting period). At my 6 week check up I was not cleared to return to work. I sent the forms over to Metlife to extend my claim. They closed the claim stating that I reached the maximum allowed benefit. The benefit for maternity leave is 6 weeks (technically 5 weeks) but I wasn’t cleared to return to work for medical reasons (they spoke with the doctor as well). If I paid into a 13 week plan, I’m not understanding why the claim was closed.