Surcharged for item returned to sender

I sold an item and used the services of Interparcel,the courier being UPS,the item went to France but the customer was unavailable at the time of receipt,and so forth the item was returned.Interparcel advised that UPS surcharged them £30.00 for returning the parcel to them,However,upon speaking with UPS they advised this was wrong and they should not have been surcharged.Interparcel are still pursuing for the £30.00 surcharge and whatsmore,they are threatening court action plus plus plus.

After using their services for 3-4 years there is obviously no customer loyalty whatsoever and they obviously do not care.I have attempted to reason with them over this but they still continue to threaten me.The worst of this is that the item sold for a mere £20.00 and they have now disposed of it.

I cannot stress enough that they are not only disloyal to long term customers but with their threatening behaviour it is absolutely disgusting.No I would not recommend them whatsoever,their customer services are utter rubbish and Neanderthal.