BMW computer

We recently came across an issue with our 2010 BMW X3. We live 190 km away from our nearest BMW dealership and have been having a local accredited mechanic change the oil. Recently, when a red light came on indicating problems with the oil we contacted BMW and they requested the car not be driven and be sent to them, which we did. We subsequently learnt that change BMW need to reset the computer after each oil change and our mechanic didn't do that. We were unaware of this, or of the consequences. BMW also informed us they would not give the information required to reset the computer and that we could only get the oil changed at a BMW dealership. We feel this is an unreasonable and wanted your opinion.