I got a call from Optus about 10min ago as well. He seemed to be we'll aware that it's to do with bankwest which makes me wonder how long this will last for before the terms and conditions are changed.
Also so just got off the phone to bankwest (didn't give account details or my ID) and they confirmed with both the PDS & with colleagues that there should be no limit to the number of transactions per day. Makes me wonder if it is purely a security thing and whether it can be overridden somehow on their end? Or perhaps it's 50 per merchant before they stop you? Has anyone tried paying multiple vendors? Optus and Telstra for instance?
Must be costing Optus a fortune to process the payments.