we are at a disadvantage when buying parts for a long term project. i had a similar issue with a aluminum fuel tank that i paid the 4 bills plus adding in an in-tank efi pump. the internal line failed the second time i started the motor, when i dropped the tank and pulled the pump i found the fuel line marked ''not for immerssion in fuel''. i wrote the company to no avail. i had to drop the tank 3 more times over the period of 3 years to replace the internal fuel line and could not find a suitable methanol resistant line.
the last time the line failed i was coming home from the power tour in june and had to but a jack and stands, drop the tank and fix the line on the side of the road. i trashed talked this vendor on multiple forums including hotrodders.com. i finally got the attention of the vendor on the 67-72chevytrucks.com forum. the owner publicly berated me in the forum for trashing his product. luckily i had saved all my correspondence with his sales people and sent it all to the owner with dates and contacts. he agreed with my issue, sent me 2 methanol resistant lines and posted that i was a fair guy to deal with and that we had come to an agreement.
post the name of the vendor, don't get personal, post the facts as you did above. post this same information in as many forums as you can, eventually someone will take note. the internet is a very powerful tool
on the other end of the scale is vintage air. i had problems getting my ac working 6 years after i bought the kit from vintage air. i talked to tech support at va, who happened to be the owner. he knew the issues involved in a long term project and sent me parts (at no cost to me) to get my ac working.
you can't buy an endorsement like that ^^^
i would recommend vintage air to anyone building a car.
and even though my problem is now fixed, i can't say that about my gas tank vendor.