2014 Rainsoft ec4 maintenance

Hello All - thanks for taking a look at my question. I just wanted to know what "actual" maintenance is needed on these rainsoft ec4 softeners. To make a very long and very similar story short - my system was finally installed and has been operating correctly for almost a year after a nightmarish run with this "company" who installed it incorrectly and was out numerous times on their own dollar, not mine. . "the company" keeps calling me telling me I need maintenance on it. My fear is that after all the problems I had with "the company" - they will screw something up and I'll have to pay for something that was not originally not broken. I am a big DIYer guy and if it IS something I can do myself, I would rather do so. Appreciate your insight. Thank you