MTN says my payment is missing and continues to suspend my service.

Just after Lockdown level 5 was announced, I went into MTN V&A Waterfront to discuss downgrading my business package as I'd lost all my contracts and could no longer afford the approx R1,800p/m fee. (I work mainly in the theatre industry, so enough said.) The experience at that particular MTN branch was extremely stressful - from the store, I was told to call one of the relevant departments and was shunted from pillar to post for an hour or so, with no results achieved. A waste of time. I then received an email in April suggesting I apply for COVID-19 relief which I duly did, attaching all the necessary documentation: letters confirming termination of employment. To cut to the chase, it's now end July 2020 and I've still not heard back regarding that. I am now up to date with my arrears having paid the excess owed last week, 22 July, and I sent the PoP to MTN Gardens Centre, my go-to store for the past few years where I've always renewed my contracts and received great service. Following up a few days later, I was told that the payment was 'missing'. You can imagine my anxiety. So, my phone remains blocked which means I can't do online banking, renew subscriptions like iCloud and Dropbox, can't make or receive calls, and worst of all, I have app**** for several jobs but anyone interested to speak with me now can't because I've no MTN service. Aside from applying for the downgrade, I've been in to the Gardens Centre store 4 times (travelling 2 hours in from Robertson each time) to try and resolve the issue, because I can't raise a response from Accounts via phone or email, and believe me I have been trying, FOR 4 MONTHS! It's a hot mess and I'm at the end of my tether with this. Allison van der Spuy