Not sure if that hotel offers valet service for laundry but I would check. I can't help much with the Hotel Zone but (the "tourist") Walmart has a laundry. Separate from the store, and the entrance is to the right of the right front door. Better than nothing maybe.
There is a laundry in the hotel zone at KM 7.5. They have drop off service and machines to do your own. They are located in a small strip mall across the street from the El Presidente hotel. There is the Super Express grocery store and a Tyco's in the mall along with some small local restaraunts. If you are taking the bus heading towards downtown you would get off at the stop at the El President hotel and cross the street to the strip mall. The laundry is about in the middle. There is a bus stop at the far end of the mall where you would catch the buss heading south back to your hotel.
Just be aware, that one is 100 pesos for 4kg, but if you want your whites separate, its another $100, even if its 1 pair or undies. I've found it much cheaper in town.
I think in town it is about $ 12 per kg now. Was $ 10 before I bought my washer and dryer with a $ 30 minimum per load.I cannot imagine not separating whites from colors. I was at Walmart today and did not notice if their laundry is still there.
I agree it is much cheaper in town. I just wanted to let the OP know that there is a place in the hotel zone. There is a laundry service on Coba just before the bus stop for Market 28 if I remember correctly. As TJ posted I believe they are charging 12 pesos per Kilo. About half the price of the one in the hotel zone. I guess it's a matter of how much value a person puts on their vacation time. Four kilos in the HZ would be approximately $4 US more.