Very bad service from Computershare

Computershare is handling the payout of a special dividend by the Vodacom YeboYethu share scheme which is due to me as an ex-employee. I sent an email to Computershare on 31/07/2018 and again on 23/08/2018 to update personal and banking details. In September, I contacted them to verify that ALL updated had been actioned and this was confirmed. On 01/11/2018 I received an email from Computershare indicating that they did NOT have bank details on record for me. I tried to contact the call centre, either getting no response or being told that the system is unavailable. On 02/11/2018, I finally man aged to speak to an agent and provide my bank details and was told that it takes about 3 days from the information to be uploaded. On 05/11 and 08/11 I again contacted the call centre and on both occasions was advised that the bank details had not been loaded. It was during the course of these calls that I was told that somehow their system had deleted my bank details. While this may be the case, there was not reason why they could not update them as the information had already been supp**** to them (in July and August). I then asked to speak to their complaints department - this department does not answer the phone. Reaching the Call Centre is near impossible and being able to contact the Complaints department is absolutely impossible and it seems that their Admin section is very slow in actioning updates. Due to their carelessness and inefficiency, the special dividend due to me has not been paid and thus I am not able to earn interest on this money which as a pensioner is important to me. All in all, a very bad experience in dealing withe Computershare.