I have seen the odd post from other Sellers about both EVRI and Packlink overcharging on weight. If this is a regular thing, you could do what they do... photograph the package on a scale showing weight before sending. Then you can contact their CS with evidence to ask for a refund of the overcharge.
Having done all you can, if the situation continues you could get them investigated by contacting the ombudsman. In England this is the Postal Redress Service (POSTRS), 'an independent organisation which can resolve disputes between postal operators and their customers when operators have not sorted out the complaints through their own procedures.' Good luck with your selling!
