Penalised for being a loyal customer

I am a Vodacom customer since 1994. Paid my account religiously every month until earlier this year when Vodacom did not allocate my funds correctly. <br> <br> Now they have the audacity to refuse me an addition to my contract because of THEIR mistake. <br> <br> The first mistake in 21 years - on their side - and now I am the culprit and penalised! <br> <br> The cheek, maybe time to move?