Nissan Micra 2012 (K13) heater only blowing out hot air even on cold setting

[Aims]

Can someone recommend a specialist who can help repair or replace the white clip that holds the wire cable that controls temperature knob. Apparently every time I turn the knob from cold hot or vise versa the cable slips out causing hot air to only blow out and no cold air coming out of the AC. Pls can someone advise? Thanks Aims