From a retailer's perspective.
A retailer always wants to treat the customer with the best service possible. Which is what we strive for at my company. But there are times where the sitiuation is beyond our control, as we are not the maufacturer of the item. The most we can control is the stock level and price, and help the customer get RMA/warranty service if need arises. However many customers feel that they should only be dealing directly with the retailer when any problems arise with defective products with which warranties can be voided, and this is incorrect. As the warranty is directly offered to the end user by the manufacturer, in some cases, lazy maufacturer side CSR reps will tell the end user to contact the retailer to start a wild goose chase. This can be avoided by keeping a track record of your RMA/refernce number, and noting their names and position, and times of day that you spoke with the reps. This information should never be used to INTIMIDATE/THREATEN them, as they will leave a note in your CSR/RMA file, and you will eventually be ignored if you verbally abuse the reps. Just documented to show that you've attempted to get a resolution within the warranty period.
Similary you need to realize that each sale is a small drop in a giant ocean, so don't expect them to move mountains when your problem is simply a molehill. Eg. If you need RMA service, don't complain about shipping costs, they're offering you an option, you need to bring it to a specific location, there is processing involved if you need the retailer to do it on your behalf.
One final note, unless you get an RMA number/authorization, DO NOT SHIP ANYTHING BACK WITHOUT PERMISSION, as your item WILL GET LOST, and or IGNORED.
Shipping things back without proper documentation is a big no no, to either the retailer/manufacturer.
I've had a lot of customers send me stuff back with nothing more than a return address. This makes it incrediably hard for the CSR/RMA department to process the item, as we do not know if the buyer needs a refund/exchange, and the nature of the problem. Always include a copy of the invoice, always include a copy of the RMA form. Always mark the RMA number on the package.
Thats all I can think of for now...if you have any tricky returns/RMAs or stories I'd like to know (through PM of course) as I'm currently looking over the RMA process within our company.