suspect an off yoghurt

This morning as usual i ordered sandwich for my principal, which is the bacon and egg on rye bread. i then decided to order the Tropical breakfast for myself, which is plain yoghurt, fruits, honey and muesli. it is not the first time eating that from Mugg n Bean and i love it. but this time it was a take away normally i will eat from the store. upon receiving the food, i was too hungry dished it up but i released that the yoghurt is not as smooth as i normally get from the shop, it was a bit lampi and stringy but tasting kinda normal. after eating after 20-30 minutes my stomach started making noise and being painful. i havent eaten anything since last night that was the only thing eaten. calling Mugg n Bean speaking to the Manager, SARU she said \sorry"but there is nothing she can do. later she then called me saying she has checked with supplier and checked the yoghurt there is no such of an off and stringy yoghurt. as am writting am feeling sick"