Okay - I suspect the author is going to require a mirror with molded surround that clips to the positioning assembly - they state "...the right side mirror got stolen..." and also "just the mirror not the whole assembly".
My read is:
* The theif did not break into the car and detach/unbolt the whole side mirror assembly; or rip the assembly from the side of the car or the part that pivots from it's stump (both of which I think would have done sufficient damage to the assembly to render stealing it not worth it - unless for maliciousness).
* Rather they detached/levered the mirror from positioning assembly - the mirror glass is molded into a surround that clips to the positioning assembly. If they did remove the actual mirror from molding they would have destroyed the molding in any case.
Unfortunately I suspect this will discount most 'self-adhisve' and stick on options, as it would need to be done to the mounting plate that makes part of the positioning assembly and like the FD - see
HOW TO: i30 Side Mirror Cover, and Indicator, Removal/Replacement - FD MY10 - it probably isn't flat... (images of the mirror molding for the FD & GD feature many design elements).
I am sought of assuming it was stolen for the same reasons as the author can't find one - i.e. lack of parts due to low number of sales and someone has/had an i30 with a broken mirror; of course can't discount someone just wanting it or it was malicious theft. A quick look on ebay, etc. leaves me with the impression the OEM part is i30 specific
This probably also excludes finding one at the wreckers - there won't be many examples at wreckers.
I found this -
Mobis Heated Side View Mirror Right Side for 2012 05 2015 Hyundai I30 | eBay - approx US$32 to DR... I suspect, in the end, this may end up being the fastest and/or cheapest route for the author. At the very least the author can use the Part Number
87621 3X000 to research further local options.