My point is, if Wizards don't use regular pens, they shouldn't have access to cellotape either, do they? So, was Ron allowed to use it to fix his wand?
It is Spellotape, not cello tape
Ron was having far worse problems. He had patched up his wand with some borrowed Spellotape, but it seemed to be damaged beyond repair. It kept crackling and sparking at odd moments, and every time Ron tried to transfigure his beetle it engulfed him in thick gray smoke that smelled of rotten eggs... (CoS)
As such, it is a wizarding item, not something produced by Muggles, that means that he is both allowed to use it and has access to it.