What sort of carpet is it. Strange isn't quite enough info :

What is it made of. what type of construction. Going to be very hard to give you anything useful until you can answer these. The remedy, if possible could be very different depending on these factors.
It sounds silly but carpets do talk to you but have to know how to listen. The construction and fibre types will tell you how the cleaning should be done. This is true of every type of carpet out there. Can I suggest training.
edited to add.
Training is a must if you are going to tackle carpets. But for now if you can get some info on this particular carpet I am sure someone here can help.