expired tiramisu cake conflict!

I bought three cakes at pick n pay (sharewood gardens) last night (16/11/2015). Two tiramisu cakes and one black forest. The 1st tiramisu cake was excellent, and I couldnt wait for the second slice of the second tiramisu cake. When I ate the second cake, the taste was awful, when I checked the expiry date, I had expired. I went ro pick n pay this morning and the supervisor was giving me an attitude. They offered a new cake but I had to refuse and want my refund because the people working at the bakery we npt sure when the cake was baked and didnt know if the cake is not spoilt. Dont trust pick n pay at sharewood gardens brakpan.... so disappointed!