Appalling service for a minor issue (missing payment)

I know as a country we have serious issues that we are faced with however, when it comes to my money & poor customer service I get extremely upset. Long story short, I have an account with Woolworths which I didn’t not pay for a couple of months due to personal reasons. Eventually when I get to pay my account the way I’m supposed to I get poor treatment. Early this year I’d receive calls from Fusion credit solutions harassing me to pay my account. On the 7th of this month I paid my instalment as per the email/statement they (Woolworths) sent to. On the next day I paid again R400 which is reflecting on the statement and the R180 that I paid on the previous day is nowhere to be seen. I called Woolworths head office to query this and I was asked authentication questions which I answered. I changed my email address & contact number, the lady gave me an email address where I can send the proof of payment and call again after 5 minutes to check if they have received it which I did but they kept asking the same exhausting questions each time I called them. What is the point of the email if I need to call each time I have sent the POP? When I was playing my part of paying they sent Fusion to harass me with calls but now that I need their help with rectifying their mistake I have to send emails & call them and get asked the same questions ? no guys I feel I’m not being taken serious. Why not take my details down and check on the system then call or send an email rather to say “we have received/not received the payment”? Why must I keep calling when the email they gave me keeps coming back saying “mail not delivered, sent back to sender” the email address that I was given by 2 ladies & a guy is *** and I sent to that email but still when I call them they have not received the POP. How though when it’s the email address they gave me? And also, why do I need to call them when they were calling me when I wasn’t paying or is it because they’re getting what they want now they don’t care if my payment gets cleared or not? I waited the whole day on today (Thursday) thinking I’d get a call or email from Woolworths saying they have/have not received the payment but the POP is there but no one bothered because they’re too busy to worry about small change??♀️ It can be a small change to them but to an unemployed person R180.00 makes a huge difference.