Hi. Did you buy it new or preowned? I could indeed be blacklisted (you would need to go via your carrier for assistance with this). Otherwise, you may need to have its firmware reloaded.
Signature: I (as a co-founder of this site) have offered online support since 2014 but have now (as of Oct 2016) given up my shareholding and am now with http://www.saroms.co.za