Shameful Identy/Truworths behaviour

Been paying my Identy account in store for ever. This October I did the same thing, went in store, the cashier scanned my card and gave me the amount due. What I normally do I will up the amount to the next hundred. Now all of a sudden I got an sms stating that I've missed my October payment and that they have cancelled my all my policies on the account. Phoned Truworths/Identy head office just to be told by the consultant that I've underpaid by R94.00 and yes they can do nothing to fix it. My question now is: If a company employee *********** staff how could a consumer be blacklisted if the account payment has never been skipped, and in fact paid more than is necessary? Identity is seemingly just doing their thing not minding if consumers are the backbone of their existence, Truworths should be ashamed of this is their attitude.