CANCELLATION OF WORK VISIT VISA BY EMPLOYER

I have a 5 year (1825 day) Business MERE Visit Visa which permits me to work at 6 month intervals before exit and re-entry. My employer tells me that at expiration of my contract they will issue a Final Exit visa and my Business Visit Visa must be cancelled.

Is that true? Any feedback appreciated.

Thank you for your kind response.

Suppose I confused this visa with a previous one I held from 31/03/2009 until 26/03/2013 where I freely entered & exited without cancellation. That visa was for visit purposes specifically without permission to work.

Current visa permits working as sponsored by my current employer.Thank you once more.