Pathetic service

the worse customer service ever. I did my duty to stand up from a night shift to go and pay my account on the 27th of June, they had system problems but the payment went off on my phone. A few weeks later i receive a message stating my account is in arrears. on the 20th July i made contact with them over the phone they said i should send them a statement which i did on that very same day, a few days later i receive a message once again stating that it is in arrears. i called them about 3 times after that again to find out what is going on nobody can give me a answer. I called on the 26th of July again to find out what is happening they said they will give me a call back yet again i had to phone them back again today 29th July . i don't get how i have to phone this people over and over again knowing i made my payment and everything just for it to still not be resolved. This is the worse customer service ever, they make it seem as if i never made payment which i did long ago.