I've tried everything to make a call to Spain and have been unsuccessful. here's the last thing i've tried:

1) selected country 'spain - +34'
2) dialed number '902 24 02 02'

Any ideas why this won't go through?

Strange
0034 is correct code so +34 should work.

There after a number like 966 774 999
would be +34 966 774 893

I tried it works.
Do you have credit, have you tried a different number, if you PM me I will give you my number (in Spain) to try