All my credit is just gone

I placed a few orders online during lockdown , as far as i understand i had credit availble to do this because how else can i place an order if i didnt have credit .As i placed my orders whatever i ordered the amount would be deducted from my credit available . i initially asked for some of my orders to be cancelled on the 30 April but only received a response today saying some of my orders have already been dispatched . Today when i checked my credit available it showed R0 , how in the world is that possible if i know i had over R1300 credit after my last order . i am seriously failing to understand . this is not the first time this has happened to me its the 3rd time , if this continues i just wont pay my account and tfg can do whatever they feel like it . sort this out is all i ask ,i dont see why in a time like this when we have covid-19 to deal with i still need to stress about an account that i pay every month mind you