magnetos

Hello all, First time I've posted on here and I'm looking for some advice; kind of a long story so bear with me. I'm a flight instructor working toward a job in the airlines and I have more than 1400 hours so I'm almost there. I have, however, got this situation and I'm looking for advice on...

So it turns out my mags have not been serviced in 821 hours. Where do you guys get your mags?