Unprofessional service !!!

I received a message on my Garmin Nuvi 3790 to update my maps. I downloaded the maps from Garmin Express on my PC. After I successfully did the map update it kept on freezing at the stage were it says "loading maps". I took it to NavWorld in Centurion to have a look at it. First of all, the Afrikaans speaking lady at the reception was very unprofessional, while I was busy explaining the problem on my device to her, the phone rang. I had to wait for a full 10 min. for her to finish her conversation with the client on the other side, who was also having problems with his device. I had the wright to be served first, as I was already in the shop. She then handed the device to the technician in the shop who tried to fix it on his computer. After waiting another ±20 min, he explained to me that the device can't be fixed and I need to buy a new one.. I was very upset, as I told him that this problem only accrued after the map update. They then told me the last option is for them to send it in to their technicians in JHB. I immediately tell them to go ahead, as I need the device on a daily basis. .The device was top of the range and very expensive at the time. I couldn't go without a GPS and after I left I went straight to the nearest Outdoor Warehouse were I purchase a Nuvi 2589 for R3285-00. A week later I received a call from the lady, just to inform me they had a look at it and it's not repairable. The next day I went back to collect the "broken"device as I thought it can only be software issues and I would give it a last try. I did some research on the internet and came across people with the same issues. I tried their tips and ......WALLA ......it's working again and with faster response time. For me It was so unnecessary to spend so much time and money if the people at NavWorld new their job. This is unacceptable from this Garmin dealer, as they need to train their staff properly. I would never ever refer any clients to them as their lack of professionalism.