Gero Yoghurt are always off before the expiry date

My dietition recommended that I use Gero yoghurt and I have been buying this product since beginning last year. Firstly the product is always out of stock especially the small yoghurt(6) so I always opt for the big one of which lately it has been giving me problems it goes off before the actual expiry date and I always have to throw it away so last week I went to Checkers with the sample of the yoghurt and I spoke to a manager by the name of Paul he said he will show the product to the supplier and they will call me Thursday that didn't happen so I went back to the shop with another yoghurt that was off and he said no the supplier will call you as I'm still waiting for that call today. I'm very disappointed with this supplier if there was another alternative please advice because I have been throwing away a lot of Gero yogurts and it's not fair.