Charged full price even though items ordered were missing

I ordered from Checkers Bryanston and I did not receive all the items I ordered even though the full amount was deducted from my credit card. I queried this and the store credited my account with an amount less than what is due back to me. I sent another query and they have ignored me since early October. I am very frustrated with the process and all my emails have been ignored and the matter not resolved since with 9th October.