question about converters

One more day-more BS. Im DONE with these guys at Dynamic. Attempted to negotiate a fair swap on this 11" converter they claim on their internet site has a stall speed of 2600-3200 rpm (which would work just fine) Afterall, they GAURANTEE their product for 1 year and WARRANTEE for 5 years, right? After 11 phone calls since Wednesday, they insult me by offering $100.00 off towards their 9 1/2" and I would need to ship the 11" converter TO them at my expense. Thats $40.00 for 3-5 day, nets me $60.00 off a $600.00 converter. Their net profit would be a total of $1,000.00 for one converter sale, and then he'll RESELL my 11". They wont take my credit card- certified bank check OR money order only.. Credit card purchase offers the consumer protection-they claim its a "problem" to credit an account $100.00. My *** it is, I own a small business and its easy. I'm steaming over this company and their smug attitude. My engine builder invested a considerable amount of time with them trying to fit a converter that would work for me into my budget and this 11" was ONE of the recommendations. What kills me is how Dynamic "can diagnose" from Delaware that the converter "works fine", just the "wrong choice"....The 9 1/2" they make is the solution to all of lifes problems.
Mancini racing sells these converters-AND they have a slight problem with these guys! Dynamics specs are a conflict with real world findings-flat out FALSE ADVERTISEMENT. Go check out their website yourselves. Mancini does not advertise the 11" street as a 2600-3200 stall speed, instead they use a 2000-2200 rpm spec. A call to them reveals the 11" street converter is not as good as advertised and is one tight *** converter!
I would have considered a full refend, I'll pay to ship their lump of crap to them to pawn off on someone else, and eat the labor , then purchased the expensive 9 1/2" from them and been done with it. Based on their "GAURANTEE" and falsely advertised converter specs I believe I was being more than fair.