Account supposedly in arrears

<p>I purchased goods on my account in last year. Since i did not receive a statement the first month I was told telephonically that my instalments will be R55.00PM which I proceeded to pay religiously. I eventually received a statement in Nov/Dec with a balance of approximately R270.00 and showing that my instalment is indeed R55.00 which I kept on paying. End April 2017 I receive a call saying that my account is in arrears. I questioned this and was told that in February 2017 I would have received notification that my instalments will increase to R110.00PM. I asked for an explanation as I had not made any other purchases since the initial one and that I received no such notification. Subsequent to this call I've been receiving calls up to thrice a month regarding this matter. Every time they phone I tell them the same story and that I do not consider my account to be in arrears. Every time they say they will put a note on the account so that the admin staff can get back to me with an explanation. Well, that has never happened. This week alone I received two calls, the last threatening legal action and that my account is in arrears as I have not been paying it. My payments for the past 8 months are as follows: July R200, June R140, May R115, April back to December last year R55 every month since this is my actual instalment. This totals R730. And now they want to hand me over. IS THIS EVEN LEGAL??</p>