N5 to N6 certificates from 2011 I have not received them

Iam Samuel I did my Netted courses at TNC Rosslyn campus on 2011 from N4 to N6 but I only received N4 certificate. 2012 I went there but they couldn't help me then I tried communicating with them via telephone but still it was the same because once they tell me that they are transferring my call to the relavent person the call return to the receptionist then she tells me to try again later on.

19 Feb 2018 I went there they couldn't find my certificates, the advice I got from them is to apply for the new once I did just that and they said I must try to call them anter 6 weeks, I did but unfortunately my certificates where not bag they said at least after 3 months but still nothing

My friend app**** his N6 diploma he did receive it but still on my side nothing. September I called again they said they just changed their system I must just try to call them November of which I did that but still nothing.

This is really hurting me coz I just have statements. At Department of education they said they can't help me because what if m still owing the college I WOULD BE REALLY HAPPY IF I WILL GET HELP