Thermomax Solar Panels

typhoon

does anyone know much about them? the previous owner of our house installed Thermomax solar tubes on the roof and an SMT100 controller. But it appears to be faulty! One of the tubes on the roof is missing, and the temperature on the controller never goes about about 15 on v warm days, up until last year or so it would have been up to about 75. We thought it must have just been cheap and useless, but the man who put our loft insulation told us it should be giving us a good amount of hot water and we should get it serviced and get the tube replaced. We don't know who installed the panels and Thermomax in Bangor appear to have closed down. Does anyone know who I would get to service this unit and how much it would cost roughly???