These guys are a company who sell accomodation vouchers. They facilitate deals for hotels. I purchased a voucher that allowed a discount on my booking and food/drinks credits. They do call a bit to follow up on purchases and try to sell you more.
You are most probably on their call list if you have made accomodation bookings through booking.com and other sites like that.

I received a call from this number and the person stated that he was calling from Oaks Pacific Blue Resort in Salamander Bay. He was trying to offer a deal in which he required an immediate downpayment. I contacted the Oaks Hotels and Resorts group and inquired as to whether they were associated with the number. They responded that they were not. Number blocked.

I called back number (02) 4016 0412 rang 5 times then goes to busy tone.