First off, your complaint does not make much sense. There is not enough information to sound valid. How long have you been taking your truck to Valvoline? Do you always do preventive maintenance on schedule for your vehicle? How old is your truck and how many miles were on the ENGINE? Valvoline offers a limited engine guarantee where if you started using Valvoline before 125, 000 miles and continue to use Valvoline oil every 3, 000 miles as recommended and any problems occur with your engine no farther than 150, 000 - 300, 000 miles (depending on grade), Valvoline will pay to replace your engine, including labor. VIOC' offers a 100% Satisfaction Guarantee with almost all of their services which entitles you to a full REFUND if you are not satisfied with the service. Did you bother to file a claim with VIOC while you were there, or did you heed all the precautions after talking to the manager? Were you willing to let them help you, or just wanted to bitch? Based on your typing in all caps, probably the latter.
In regard to Mr. Evans comments, you work at an independent quick lube shop. From the sounds of your problems with VIOC, it is most likely just the location closest to you. There are many other independent shops that use Valvoline products, and if you assume that the filter dictates where the previous service was, you're just as naive as the techs that strip out the oil pans and double gasket the filter. A lot of people could have similar problems with Jiffy Pube or Walfart's tire center.
If the customer has a problem with their previous service, they should worry about it, not you. If you don't want their sloppy seconds, then direct the customer to where they had their previous service.