Poor service delivery

I bought books in February which was paid for then. i was told that the books will be available in 2 weeks which i accepted and when i went to pick up i was told some was still outstanding. i received a call in april to pick up and my husband collected the books but was told that one book is still outstanding. because the books was only due for second semester i accepted their apology. now i am in need of the book i went to collect and am told there was price increase in May not only for the outstanding book but on all books which i have already received, i must now pay additional +- R200 does that even make sense really. How does a price increase affect me when i paid in February and received other books which have been affected by the increase when it is poor planning and service delivery from the branch side. i have spoken to the person who assisted me and his manager and they still believe i need to pay. but really they delayed me getting my books now i have to pay price increase that doesn't even make sense. all i want is my outstanding books as i have started with the subject now am going through hassles to get it.