There is a huge thread called Colinas de Lago on here which I participated in. I think there are quite a few properties still with problems which boils down to the Orihuela Costa town hall and the now out of business Tecnologia Urbanistica.
However, we purchased back in 2002 with the above. We paid cash (then €106,000 or £77,000 at the exchange rate). The builders took out a mortgage on the land in order to build the Colinas de Lago developement in the sum of €12,000. In 2007 when we decided to sell and buy another property, we were then informed that no habitiation certificates had been issued by the town hall and the property had a mortgage on it. After several trips to court (where the builders never even bothered turning up) we ended up with a bill of over €4,000 and eventually got the nota simple (never, ever saw the deeds) and we were able to put it on the market in 2011. However, still no habitation certificate but the notary said it would be OK if we paid €300 from the sale to cover the cost of one. As far as I am aware, there are still no habitation certificates for most of the properties on Bosque de las Lomas 2 and Bosque de las Lomas 3 still has no water or electricity supplies nor certificates or deeds. Of course, house prices had crashed in between going to court and getting the nota simple and we eventually sold for €57,000 but, after estate agent fees, solicitors fees, retention fees and so on we ended up with about €48,000, quite a drop in both pounds and euros. To cap it all off, as the sale was going through we were told that, although the builders had paid off the mortgage, they hadn't had this altered at the Land registry and we had to pay over 500 euro extra to get this done. We eventually sold in 2012.
In the meantime we had bought another house (thinking the sale of the flat would pay the difference) but had to take out an unwanted mortgage on the house to cover the shortfall. It meant paying a mortgage, 2 lots of IBI, two lots of utility bills, two lots of non-resident taxes and so on for a period of over 5 years before it was all sorted out.
I hope fly380 comes on and gives an update on his property on Bosque de las Lomas 3.