abs failure

Hey there i bought a 2nd hand duke 390 old version (2016 )model and was very happy about it .when buying the bike there was some issues but i could have handled but later on i got an abs malfunction that was so disturbing .when i showed this to showroom they told that they have to diagnose it...

Rear brake disc heating and abs not working

i had just put on a tail tidy kit from r&g and i had accidentally had the wires switched around for the new tail light, so i switched them and it worked fine, when i went to plug in the rear blinkers something happened with the computer display where it shows mph and everything it said abs...