Seeff don't care about the tenants

I have been renting out a property through Seeff Southern Suburbs in Cape Town. From the start, the agent, Marinda Bienz, as been useless. Always unavailable and she never tried to sort an issue out. All her emails are written with a condescendant tone, she clearly thinks she is a diva and doesn't give a sh*t about the poor tenants. My last experience with them shows the level of their services. My outgoing inspection was scheduled for the 15th of May. The landlord has asked us to sort out a few things in the house but since, Seeff has refused to give us the keys back. We cannot access the property and have to "fix" a few things! I have asked for the keys 5 times already but I haven't heard anything from them. They have just been ignoring my emails. I am not sure what my rights are, but how can this be possible since I have paid the rent until the 31th of May?? We have paid to rent a property but they are prevented to get in!