Device

I have terrible experience with this company. I paid the subscription amount on time I even send them proof of payment, but the device was blocked I sent them email ask them why it is blocked they me that it because I didn't pay the subscription, I sent proof of payment again they acknowledged it, and the phone was unblocked after 2 days the phone was blocked again. I asked why it is blocked I was told that because I didn't make payment, I sent them proof of payment for the third time they acknowledged it, and I was told that the device will be unblocked was told to insert Telkom sim card with a data and I didn't so, but the phone couldn't unblock. After a day I received a call to say I must return it so that they can unblocked it and I'm still waiting for it till today. But what Is making me angry is that I'm getting emails from their account department saying I'm still owing them I must return the phone otherwise they are going to open a ******** case against me and also blacklist me.