A general guide as to the general installation an use of a washing machine.
Remove the soap dispenser regularly, and remove any softener or soap build-up, especially around the softener syphon tube. There is usually a small “cap” about the size of a thimble, that pulls off, and it should be clean and free from hardened softener, and around the pipe where it pushes on to. This reduces the tendency to leave water or softener in the softener compartment. Some AEG models have a little slide switch at the front , that can be seen when the dispenser is pulled out. Try switching that on to activate an extra rinse.
If you think that your main control PCB or timer may have failed, you may be able to get it tested, and if faulty, get a re-worked (repaired one) much cheaper than a new one.
ALWAYS DRY THE DOOR GLASS AND GASKET WHEN THE WASH IS FINISHED, AND KEEP THE DOOR OPEN WHEN NOT IN USE, AND YOU ARE GOING OUT. Obviously if there are young children are about, this is NOT a good idea, but if you are going away, ALWAYS keep the door open. This will help prevent the formation of black mould (See 10 and 11 above), that tends to form when low-temperature (NON-BLEACH) liquid detergents are used, and there is moisture left around the seal and glass, and there is reduced oxygen with the door shut.