Over payments

In early 2020 I submitted all my documents as requested by the department of labor to claim UIF whilst on Maternity leave. I gave birth in February and after numerous calls (which never got answered and numerous emails) i got assisted by Andries Roos. All documents stated when I would return to work. A week ago I received 2 letters stating i was over paid and i need to pay them the money. I emailed them asking why I was over paid when my documents clearly states my return to work date. And the amount that was due to me. This same Andries Roos whom I think made this mistake dont answer my questions and just said you need to pay this amount. First of all who ever made that mistake must answer! You wait months to get pay outs, and when there is money due to them you get final demand letters! I am disgusted in this ******* department!