Do you mean MDR-023 ?
Sony headphones are well worth keeping -- I have some about 25 years old , rewired several times and (obviously ) the sponge has been replaced too.
Fortunately the sponge used on mine is similar to that used on really cheap headphones so I just buy those, remove the sponge and chuck the cheap headphones in the bin.
Your model may be a little harder to match -- but it's worth looking in the sort of shops which sell rubbish headphones -- almost bound to be cheaper than seeking official parts from Sony.