Dual sim phones

I have about 8 vodacom contracts on my name and has been customer for over 20 years. There is one contract that I dont use and the airtime balance just keeps accumulating. Now its time to upgrade that number and I want a P8 lite dual sim phone so that I can use my main number with my other number in the same cellphone. But vodacom blocks the second aerial on the phone so that you can not use 2 sim cards in the phone<br> My opinion is that this is not correct as the cellphone has place for 2 sims while other networks alow this and who gives Vodacom the right to decide that I may only use 1 sim card on a dual sim card phone