Your new belt is probably a different length too.
Your QBK128 would fit The Younger Mrs S' Titch, which is a 1996 model Cinq'.
You needs a QBK718 probably... (1998 - 2010) but don't take my word for it. Make sure you check with the seller that a 718 (or the same equivalent another brand) would fit your car by registration number or by VIN cross-reference.
And when you take the old belt off, check it against the new one all the same.
Ralf S.