Vodacom misinformation

I am currently based in the UK. I have used Vodacom for the past 20 years. Each time I arrive in the UK I receive a notice telling me I am roaming on the Vadacom World plan and the Cost of calls and SMSs and the new Customer Care contact number for Vodacom SA (+***) and stating calls to this Number are FREE. I have had occasion to contact Vodacom SA on this number but they charged me R65 for this call. I challenged them on this and provided screen shots of their notifications and their 'Contact Us' page on their website. I can provide copies of these if required. Their response on 16 July was - ' Dear Customer,we have completed our investigation and we can confirm that when roaming you are charged to make and receive calls and you are also charged to make calls to our customer car (sic) line. The billing is correct. as a gesture of Goodwill we have credited you with R30 airtime' - No apology, no reference to their erroneous messages and info saying the calls are FREE. Is this not theft on their part?