Exorbitant data costs

I was totally appalled when I noticed my current account and the data costs! I was traveling internationally for a few days and was very aware of the costs incurred when doing so - therefore I deactivated my mobile data before I even left. On logging in to my account I noticed an excessive charge on my data - which I have been told was due to an open line /data roaming? I have previously requested to be notified when the cost exceeds a certain amount - I have in the past received an sms or even a call when the data cost is excessive. Why did they neglect to alert me at this time? Its simply unacceptable to charge your clients such high fees - both locally and abroad. I contacted the call centre on my return and was made to feel totally *********** by a call centre agent - your customer service leaves a lot to be desired. It was made very clear that you no longer require my business.

I have been an extremely loyal costumer for over 20 years and I am seriously considering canceling my contract or simply not renewing due to the lack of service and attention. Please advise alternatively I will pursue other avenues to highlight the inefficiency and exorbitant fee. My account is usually very high with data costs but this account is simply exorbitant and totally over the top! I wa