As you know (presumably), Playacar is an upmarket gated resort community about 2 miles south of Playa del Carmen. I was in PdC earlier this year, but not in Playacar, so don't know if any of the resorts have ATMs within them - I doubt it but check with your resort hotel perhaps - most have websites. Also on many resorts, in the hotels themselves they run a cashless system where you sign for services and pay by creditcard (or cash) at the end of the stay.
As the above link indicates, there's plenty of ATMs at various banks in PdC. I used these to get pesos out - no problems. On this coast, there's so many US tourists visiting that virtually all shops with any tourist link accept USD and most PRICE things in USD, not pesos. However assuming you are UK-based, there's no point taking dollard because you will lose out twice in conversion of currencies.