Amazon France return shipping

Hi folks

I bought a Sony soundbar from Amazon France warehouse. Item wasn't as described. So initiated a return contacting customer service. I paid £65 for it. The return address is to the Amazon centre in Slovakia. Item weighs 4kg.

Took the package to Royal mail who quoted it be £47. They said to try different carrier as its so expensive.

Anyone done similar return? Looking for some advice please.

Thanks