Poor service

1 week ago a 50 kg of chick chick 2 cost R 305 , overnight the price has shot up to R405 ! Please can someone explain this? Especially as petrol price has come down and there is no longer a drought in Gauteng . I have been buying 1 x 50kg chick 2 and 1 x garden seed 50 kg once a week for 11 years and have never experienced such a huge increase?