What you haven’t told me is whether the oil was actually low when the warning light first showed up on your dashboard (and before you topped up the oil). Perhaps the person who changed the oil didn’t add enough oil afterwards; perhaps they didn’t account for the extra half a litre required to fill the new oil filter. Even draining the oil to change it could, conceivably, cause the low-oil light to trigger, and if that’s the case, you need to re-set the light once you’re satisfied that the oil level is correct.
Re-setting this warning light varies from car to car, but an actual mechanic would probably know how to do this, so maybe a quick visit to a workshop to have the light re-set will be worth the small cost involved. By the way, I never rely on warning lights to tell me my engine oil is low. That’s what a car’s dipstick is for. Check it each week and you’ll never run the engine low on oil.
