Constant incorrect information and call dropping

For the past 3 months I have been checking when my upgrade is due. I have not defaulted on my account. I have however logged a query as it seems I was overcharged on a service. which Cell C has to date still not managed to resolve. I tried upgrading last month, the agent did not find any problems on my account, but the phone I wanted was not in stock. Today, I make my selection, call in and I am told I am prelegal. The agent tells me to contact the Prelegal Department to clear it. I contact them, call is dropped several times, I am transferred but the line just hangs, this goes on for about an hour, possibly longer. Eventually I get through, the agent says no, the account is clear. Again, I call upgrades and I am told the account is prelegal!How is that possible when I've been credited R42.55 last month for overpaying the account! I've had several disputes with Cell C, the service is beyond horrible, if my company did not insist I contract with Cell C I would not be taking an upgrade right now. The complaint is the start of a series of actions in steps required in order to get assistance. Kindly resolve urgently. I may be contacted within the next two hours. Thank you