FlySafair charged for Priority Boarding but did not deliver, and refused a refund or credit

My husband and flew back from George to Johannesburg on Sunday 7th July on Flysafair FA 227. We specifically paid the additional amount for Priority Boarding. On queuing for the flight, we mentioned to the ground staff that there were people in the Priority Boarding queue who hadn't paid for that privilege. We were told that this decision was made to facilitate better boarding. This was not the case as we found ourselves standing on the tarmac waiting to board in the rain. By the time we got onboard we were soaking wet. I then contacted Flysafair to ask for a refund and was told they don't refund for Priority Boarding. I was not even offered this as an option on my next purchase -- just told 'sorry we don't offer refunds'. For me it's not about the money, but about the principle. You cannot offer a service at an additional cost, then not provide that service and refuse to refund or credit your client -- that's *****ing. Very disappointed with this attitude, considering the airline in most other regards is actually very good. I may well consider taking my business elsewhere just on principle