PAYMENT NOT ALLOCATED SINCE 29.06.2015

I made a payment on the 29.06.2015 and used the reference and bank details I used previously. I have been getting calls and threatening messages from a third company called ARA Group who I believe handle builders warehouse accounts on behalf of RCS. I have send through the proof of payment at least 7 times and was even told my payment was found and needs to be allocated to my account. I call and they promise to return my call and obviously nobody does. there never seems to be a manager available to escalate it to an if they unhappy when you start shouting out or frustration they just drop the call. Got an sms at 4.30am this morning and called the head office and send through the proof of PAYMENT again and promised I would get feedback by a supervisor in the department and how gullible I was to think they would actually call me back. All the sms's are in capital letters and I can only imagine what my profile at ITC looks like. Bunch of idiots, I WILL close this account soonest as I cannot put up with such a useless financial institution.