CREDIT TAKEN

I have a contract with Vodacom on *** for almost two years, contract end November 2016. This number should have been cancelled and transferred to my ***, which did not append. Now Vodacom is saying that i lost the credit of each month that i did not use. This is from inception until the end of February 2016. This R150 a month for all these month. Can you please sort this matter for me.