Discovery sold my personal details- I am now prone to identity theft

I joined Discovery November 2018, I was advised I would receive my card in about 2 weeks, that never happaned. I called them n emailed them in January and the person I spoke with advised that they would send me another card to my work address and that too did not happen. I called sometime in May with an enquiry about their coverage and asked about the card again. The lady I spoke with advised that she would send it to my work address again. Now I received the cards beginini July 2019. My issue is that the envelop in which it was delivered was not sealed, at all. I opened it to find that the cards had my full details on them. This then means whoever came across that envelop had access to my personal details, my full names, my ID number and physical address. I did let Discovery know about this concern as identity theft is real. At first they were proactive and trying to help however now they are giving me the "we will get back to you" line. I m honestly concerned as I know someonwe who had their personal details used to open clothing accounts which he was not aware off.