I think we've got some confusion here.

Firstly, you talk about paying $70 for 10,000 points as being a ripoff... but that's essentially what a points-and-cash booking is. The cost of your room is reduced by 10,000 points, at a cost of $70. Same thing for all C&P bookings.

However, something's wrong in your particular case. What was the original points price of the hotel you booked? If it was 20,000/night, then IHG deducted too many points for your stay; if it was 25,000/night, then the booking should have read 15,000+$70.

Is this a case of a booking made, then the points per night increasing for the hotel?