I agree the outer casing is cheaply made and splits causing the cable to get trapped between both halfs.
I have one of these and it’s not the easiest to wind it and pull out.
With reels you should unwind when using to stop them overheating Anyone thinking about using for home office etc have a read below. Why unwind the cable completely at high load? Where electricity flows, the use of electrical devices also generates heat. If more electricity flows through the use of several consumers, more heat is also generated. If electrical cables are wound up like the cable of a cable reel, the heat is naturally difficult to dissipate. To avoid overheating the cable, it should always be completely unwound from the drum body. Cable rewinding devices, such as cable reels or cable boxes become extremely hot in the core of the coiled cable. Therefore temperature switches, also known as overheating protection, are mandatory. Without this mechanism and the overheating protection, the cable insulation can melt and lead to destruction - or in the worst case - to fire of the rewinder. brennenstuhl.co.uk/en-GB/selection-of-themes/safety/unwind-cable-completely
10m £11 Halfords if anyone can click and collect https://www.halfords.com/tools/garage-equipment/garage-essentials/smj-power-extension-ct1010-146310.html
Your welcome - glad to help (y)