You can use a VPN to use their ad-supported free service, however, in order to pay you will need a credit card issued by one of the supported countries.
since no one is stopping you from downloading free mp3's, they don't let you use these services in lebanon,
That's not why they don't allow you to do it. The reason is that Spotify acquires a license to these songs from the big record companies like EMI. The model adopted by these companies is based on geography to maximize their profits. It only makes sense for Spotify (in terms of profitability) to license access in very specific countries that have big markets in them (e.g., Sweden, France, USA, UK).