R30 for reconnection. Is that good practise?

Last week Thursday the 12th Mweb sends me a whatsapp saying I havent paid my account. 2 minutes later they disconnect my account. I spend R60 in airtime phoning billing dept. They never even sent my invoice. I made the emergency deposit. Luckily I was reconnected so I could continue working. Now I get an invoice wanting to charge me R30 for reconnection. How is that in any way good practise?