Accredited by which standards

I own a Renault Kadjar full house. Upon my sensor light for the tyres coming on, I proceeded to Tyrenet to have it checked out. Them being RMI accredited, I thought I was in good hands. The fitter checked out the tyres and established that there was nail or other that pierced the mid rif of the said tyre highlighted of the sensor. I then gave my go-ahead to repair tyre with a mushroom plug. After paying I proceeded to leave but noticed the sensor was still to which the fitter said will disappear as I drive. I also checked with the agents who said that the sensors are self adjusting and does require resetting via laptop due to no change in position of tyre. However the next day 27/02 I noticed the sensor was still on after driving a considerable distance , at which point I sent Mariam a message indicating that i would be bringing in the vehicle for her evaluation. However , after much arguments and deliberation, Mariam asked her fitter to strip the tyre but to hers and my astonishment the sensor was missing hence causing the lights to still remain on. To this new evidence and verifying that her fitter was the only one that opened the tyre, she decided to view the camera . After a few days , she came back to highlighting the the light was off in the area her employee was working in as the retina of the camera was focussed elsewhere. Apparently after interrogating her staff, she maintains her staff as trustworthy but I find this unacceptable because the dealership is gonna tell me to take vehicle where the puncture was repaired. I also find it repulsive when the correspondences that Mariam sent states that she Mariam is not responsible especially as she highlighted that she does not employ '******s' but professional people. Please to the powers that be, I want a thorough investigation into this for accreditation of the technicians employed by Tyrenet especially being RMI accredited and S-Point affialated.