2 yr old 206 verve, service reminders going backwards, what is going on?

Q: The screen which tells me how many miles left until my car needs a service used to be normal going down, so when it got to 50 i rang my garage who said it didnt need a service for 3 months or until it reached 20,000. At 15,500 there was obviously no point so i left it, and it started going back wards from 50 upwards, and its now telling me 1250. What is going on?

A: its now telling you how many miles past its service interval was due thats all, i would have it serviced anyway, the service reminder thing is just as a guide i change my oil and filter every 5-6000 miles even tho its not due to have them until its done at least 10,000 miles

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