Vodacom 4 months theft cover

I took a cellphone contract in December, now the phone was ****** out of my bag in February. The phone came with a free theft cover for 4 months, when I went to claim, the guy that did the contract did not explain that I must use the same simcard the phone came with. He acknowledged that he made a mistake and that he will speak with his manager. The following day he came and said that because I signed that I am not taking the insurance, the claim is non and void. I went to check if this was true with other Vodacom shops, and they said that the theft cover is something vodacom was giving you as part of the promotion and this had nothing to do with the insurance. I need help to nail this guy cause he is taking me for a fool.