This number appears to be an automated VOIP-to-PSTN (Voice Over Internet Protocol to Public Service Telephone Network) interface. I just received, in London, a pre-arranged call from Kuala Lumpur that displayed +3390300. The caller was using a 'cheapie' phone card. It seems that the card company uses VOIP to get the call into Europe, then switches to normal telephone circuits once in Europe. Implication: A call from this number could be from anybody, anywhere, using a discount phone service.

I received a call from these people on my personal mobile and then home line offering investment reports.
As the numbers they called on were personal/home numbers rather than business numbers ( the ones I give out ) I knew they were not things I had signed up to.
I have received quite a number of these type calls from financial type businesses and the details they are giving me lead me to believe they have the MRI database of overseas house purchasers.
Maybe that may explain why you are getting these calls?

The guy I spoke to was pleasant and went away when I said I was not interested.

Number was supposedly a delivery service but it is a hoax for puppies for sale.  Don't know whether it charges to receive calls, will find out when bill comes in.

Got a number of calls - I thought it was via a VOIP line but no message. Dont answer unless you know the number or you can see the digits.....normally a scam

got a call from 3390300 24 Nov 2010, no one spoke, just a load of background noise