Refund not processed now phone is softlocked?

Account Number N***. I have been waiting for over a month for a refund be put through on my account ref no. ***, at which point Zanele informed me that it would take about a week to process the credit. At the end of August I checked my accounts but the credit still did not reflect, hence I did not make payment. Eventually on Tuesday I made the payments for the August expenses and sent through proof of payments. Last night I sent through proof of payments again with a new reference number ref no. ***, and now I am getting legal threats sms'd to me. Trying to phone the Call Centre is absolutely impossible as the system tells me that my phone numbers are invalid. Well if my number is invalid why am I being sent Sms's and why am I paying MTN?? The most frustrating part is that I cannot speak to anyone, there is no alternative number to dial and no way of getting through to the Call Centre??? What now, I cannot use my phones and I cannot get the query resolved??