MSC cruise is a rip-off

I purchased 2 x drink packages at $150 each. I was invoiced $356 and I enquired at reception on the ship and I was told I will be refunded. I boarded in January 2024 and I have been querying my refund since then. Now I am told I was charged for expenses on the ship. I am very upset becasue i was charged $56 for I have no idea what and now they refuse to refund me. Please can I get advice on how to get my money back.