A cardinal rule on e-Bay, where I have been continually selling for 21+ yrs. is that one should never list an item where being defrauded will create the slightest problem. In addition, occasional sellers may have their money held until a buyer's period to protest the transaction has expired.
To modify the aforementioned for shopping, if an MSC's conditions of business are unacceptable, only deal with those companies with whom you have a meeting of the minds. I have completed 48 jobs for Confero over a 19 yr. period. Their manner of payment is acceptable to me, BUT, I respect it may not be for other folks. It all goes back to the old adage, "What's meat for one, could easily be poison for another."