Need Advice Appliance Repair for LG Double Oven??

Hi I read some rather disappointing reviews on LG appliances in general. We purchased our home in Broadlands with all LG appliances included....need a repair or service on our Stainless Double Oven. Getting and F9 error message and the unit stops preheating...it's happens occasionally but I don't think I'm getting the same temp as the panel displays. Do I still with only LG servicemen or should I call a general appliance repair? Any thoughts are appreciated. The dishwasher seems suddenly louder too but that can wait since it's still cleaning well. I hate LG.