Unnecessarily changes to IS, billing system which destroys customer experience

I am getting highly irritated to chase you dysfunctional agents to get me the invoice, which by the law i need to have for SARS compliance.MTN migrated once again to some new invoicing system where I cannot pull March 2021 invoice as I used to and from that day onwards MTN started emailing invoices but of course excluding the month of transition. 1) So my experience I called 135 number twice 2 days in a row where your system is offline every time I call2) Emailed customer care requesting March 2021 invoice, the agent emailed me June, then I requested again March and received July and now they don't bother to respond!! What's wrong with MTN as you trying 25 years, a business owner like that, and I really don't have time to educate and chase you junior and ill-trained staff. Regards Egor