Extremely delayed service

NAV car License disc renewal on fnb app is extremely inefficient. I usually go to the post office to renew my disc which usually takes about 30min. I was told by a friend that the fnb app service is efficient and usually takes a day a two to be delivered. Having being in my grace period for almost 15 days, The mistake I made was using this channel for the first time to renew my license disc. After a week, the tracking comments says its with the agent with no further details. My disc has now expired and I intend leaving for a holiday within the next two weeks. It's extremely frustrating having to wait and not being in control of the situation. I'm not sure whether to just go to the post office and do it myself again and continue driving my car with confidence? Will fnb offer a refund if I do this? Can I collect it instead of waiting for the courier? Can we communicate with agent?