Packaged food contaminated with soil and no response from Spar customer care

I bought a 1kg bag of Toasted Granola Fruit and Nut from Aurora Spar about 2 weeks ago. I opened the bag recently and made some in a bowl with hot water and milk. Halfway through I bit into a sand clump and there was sand everywhere in my mouth, teeth and gums. I spat it out and had to rinse my mouth out. I assumed as it was a "natural" product that some soil had accidentally attached to a raisin or something. 20 minutes later I foolishly decided to have some more of this granola. The very next s****ful had another sand clump in it. Same story. I phoned Spar customer care and after waiting a while it just went to an answering service and I left all my details with this description. I've had no response. I also logged an official complaint on the website form with batch numbers etc.. Still no response. I will never be able to eat granola again and I will never eat or trust Spar prepared food as I cannot trust their hygiene standards and clearly they do not care when customers have legitimate complaints over contaminated food. Since eating this Granola I've had terrible gastro for the last 2-3 days. I do not know if it's related but it seems awfully co-incidental.