Sergio Appliance Repairs - How would I know that this is not a con?

Sergio Appliances Repairs in Rossetenville Joburg. They charge a call out fee of R600 - they did inform me of this and I did decide to risk it. They then quoted me R4000 to fix a Panasonic DVD player. How would I know that this is not a ****? Before they fetched the machine, I sent a picture of the player and told them that it is a Panasonic player. They did not say that parts for this player would be expensive, that is until they sent the quote. So I am left spending R600 for no result. They should have informed me about the cost of Panasonic parts (if that is true) and I would not have taken the risk. A new DVD player costs far less than R4000 and I am not concerned about the brand. They could have informed me - I suppose an uninformed customer results in R600 earned for driving from CBD to Northern suburbs.