"account not paid" even though i paid through store

I pay my account every single month for the last two months my card for online payments gave me issues so I went and paid at the branch to make sure its on time, this month out of the blue i recieved an sms stating I owe mr price R595 however I know my account is paid i still have the docket the store mailed me apon payment. so here i thought ok must be a mistake from their system lets try and send a enquiry regarding it on their website. I must say worst website i have ever encountered for a company their contact us mail system does not work after11 tries it finally went through the system just says sorry failed sending email. they have not came back to me yet and more threatening messages came through and now the mother of all messages came through stating that i am ignoring the message their going to give me over to the tracers even though im trying to make contact via email because i cannot be on my phone during the day and cannot take calls during the day someone please get back to me especially via mail check your system and you will see ive been trying but now im fed up