Blacklisting a Handset

I called to blacklist my ****** handset and after answering questions as handset as I can be .I am told that I've failed the test as I cannot tell exactly how much airtime was on that ****** phone. How the hell is one supposed to track airtime on a handset. I am a business man who makes thousand of calls a day and am I expected to keep track of the airtime balance after each call? This is plain stupidity as I gave all the other information requested honestly bar this airtime question. I think other service providers will offer a better customer service experience other than this hogwash so called service from this stupid Vodacom. You have your handset ****** and now you have to go through this *** service? ********.