Refused to book the Device

I'm Terribly disappointed with Telkom, sometime in October I went to Telkom in Benoni to book for my Tablet they refused to book it because I didn't have proof of purchase with me,last week I took it to East Gate the device was booked but to my surprise I was informed that I have to pay R587 for the device while I'm on contract with Telkom Shocked.my other phone is due for upgrade but I doubt if I will renew the Contact with Telkom