how can i fix my servis washer/dryer?

l have got a servis washer/dryer 900 the washing machine part works fine but am not to sure if the water heats up , the main problem is the dryer part, l have put my wet clothes into the the machine. A few times to dry them everything go's around, an works like its meant to,it also makes the same noises that its always made .The only thing that it dose'nt do is heat up an dry the bl**dy clothes , can anyone help me ? or dose anyone no what the cause of this could be ? is it fixable ? is it easy to mend ? could i do it myself ? an how much will it cost ? All help an advice anyone could tell me would be so so helpfull thanks ! ! !