what's wrong with my indesit IDCA 8350 B?

Bought indesit IDCA 8350 B tumble dryer few weeks ago. Set "ready to wear" cycle and it worked great, after over 2 houres clothes were properly dry. Couple of days later put the load in on the same cycle, this time it only lasted 15 mins and washing was still wet. Tried it few more times with the same result. Is my new dryer knackered already? Please help!