Everything still falls down to being scam. From your explanation you only understood one part of what I said earlier on. For sure, asking for payment in advance may seem to be a scam from the service renders but subsequently the client may fail to send the payment after they have recovered his/her wallet.
Asking for payment upfront is not a sign of scam but the problem is that, majority that are scamming people for this reason are mostly using this pattern so that they can run away with clients money without a trace. Some well known wallet recovery services may asked for partial payment upfront without sounding like it's a means of scamming their clients.
There are different brands that are into fund retrieval on lost wallets and due to their advancement and work ethics, they may choose to ask for payment before they start work in order to fund the the necessary procedures that is required to retrieve funds in clients wallet.
Yeah I agree totally with you on this, if the service charge is high then it will definitely scare people away from because weather or not the money in the wallet is much, people would want to recover there lost wallet so if it can be done with a reasonable and affordable cost then it will be a bonus and more people will tend to use the services keychainX has to offer
For me a favourable amount is the right thing to do as it would also allow for people to easily make use of there services without hesitations and also safety of wallet should also be guaranteed