you can go to renault and buy a new one, but unless you've got a standard exhaust i wouldnt bother.
on mine, i cut the 'X' at the bottom of the mount out, and inserted a universal mount which i got from halfords. think it cost about £2 and has lasted far longer than the renault one, whilst still being made of rubber so allows a bit of movement.
otherwise you can cut up pieces of hosepipe and insert them into the gaps on the renault mount which helps to firm it up
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