So tell them....
Hopefully in both of the cases you speak about, you tell someone about your issues. In the case of the service company that does not support IE, the more they hear from customers that they lost their business because of this fact, the more likely they are to do something about it. In the case of internal IT, start forging a partnership by speaking to them about your experience and enable them to see themselves through their customers eyes. It really doesn't matter what is behind their flawed services, the only thing that matters is getting the opportunity to continually improve.
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