TERMINATION OF MEDICAL AID

HI<br> <br> I joined a new company and wanted to join a new medical aid and before i could do that i needed to terminate my service with the previous medical aid , My last day of employment from the previous company was on the 29th which was the day i got paid and the deductions for the medical aid already went through, i called the assistant HR from my previous company and asked them to terminate my service and i also called Discovery and they sent me the certificate of service wit date of withdrawal 2015/10/31, I went to the Dentist for filling on the 12/10/15 and on the 16/1015 i went for a follow up for the blood samples at my GP but to my surprise when i got there i was told that the medical aid has been terminated i showed them what the medical aid certificate andthey advised me that the medical certificate is legit and they can't get through to Discovery accounts department because they do not work on weekends, the Dentist called me and i had to pay in R532.30 as Discovery declined to pay, why did they misled me by sending me the certificate that clearly states that the withdrawal is up to 31/10/2015 in the first place i still have the copy they sent to my email<br> <br>