This is usally one of 3 problems;
1. it heats up but nothing really dries. its all gunked up, give it a good clean out
2. it doesnt heat at all. There are usually 2 thermistors accessible under a cover at the back, they regulate the heating element and one tends to go. Do a websearch someehere like ukwhitegoods to find the fault finding instructions. Easy fix if you are handy. sometimes it is even that one just needs resetting on some models.
3. it doesnt heat at all and the thermistors are working. The heating element is burned out. You can replace it. i have done this once, and never again – to get at it you have to severely dismatle the drier and this is a nightmare as the are designed to be strong only when fully screwed together. The drum never fitted right afterwards, and the close took way too long to dry.
After fixing, buying second hand etc. I finally went for a new true 7kg load one, so I we can put the entire 7kg load from the big washing machine in and it really will dry plus it has a high level water tank, no stooping, and even a plumb in pipe so you can send straight to the drain -no tank emptying.
When you think of useage time each week divided by the cost, it works out at pence per week. Fix it or buy 2nd hand and do the same sum and it never works out in the long run.
Do the same sum on your carbon full sus and that works out ridiculously expensive???