why is my line suspended when no one has said anything to me about it and my account is now on collections??

i sent numerous emails to cellc regarding the below but they keep closing calls without resolving my case..

I have been trying to call 135 with no luck, I need to know why is my account suspended?? I was told by your agents I will only be debited for the new contracts once my upgrade date kicks in which if I remember correctly they said April. Now I recently realized cellc has been sending me 2 statements which I wasn't aware of. Why am I in arrears as I only expected to start paying for my upgrade April and if I was supposed to pay before that why did cellc never debited and only appear now saying I'm owing whereas I've been paying my standing contract as per agreement.. why did you NOT debit if you were supposed to?? Please re instate my line and sort this mess out as soon as possible. I was told this is an upgrade and that I won't be charged two contracts at once. I've been a cellc customer for so long and had no issues and will like to keep things that way.

Please note I'm unable to take calls unless you let me know the time you will call, so kindly respond on email *** with the time you will call so i can make means to take the call on the time you will advise