So Disappointed by Rain

So I signed up with rain in May this year, reason being that I didn't want a binding contract. According to my understanding it works as pay as you use, now due to life challenges I didnt make payment for 2 months and my services were suspended already. Now in September I decided to pay R559 so that I can get reconnected, on the App it showed that I need to pay only R559 which I did on the 23rd Sep. Only to get an texted on the 25th that I owe R595 and my services were suspended 🙃, just like that as if money falls from trees. No invoice showing that I made payment when I check on the App. Confused as I write this complaint, I called the call center held on for long and being told that I was invoiced. Now how can I be invoiced when I didn't sign a monthly contract? And I paid before hand to reconnect, can someone explain or give me a call. Pay as you use is exactly like Dstv etc, when you don't pay your services get suspended and when you pay you get reconnected. Otherwise I will have to look for wifi packages that does not bind me And rather refund me my R559 please. I am so disappointed just when I was recommending rain to my friends and relatives after this I will definitely not.