incorrect billing

Since January 2015 I started experiencing high billing from vodacom and was told it was data usage. I requested an investigation and was subsequently provided with a credit note. The billing from then on continued to be abnormal and when I queried this time I was told to check my data usage which still did not match the billing.Because of this I did not avail money on my bank for the debit order fearing that my money will not be refunded. On 29 May 2015 my cellphone no was deleted. I called Vodacom again and could not get help. I need to talk to someone who can tell me what I was billed for in Jan and Feb when my phone was suspended.