How do you deal with a customer who consistently hits their bandwidth limit each month but refuses to upgrade? I'm referring to a someone who normally has the "Bandwidth limit has been reached" message for the last week or so every month. Does this reflect badly on the reseller or just the site owner?

I think personally it's just a problem for the site owner. If they want to have their site down for a week out of every month then that is their problem-it is them who is suffering, losing revenue.

Unless there is some other way in which they are breaching terms and conditions I don't think you can do anything about it.

I don't see how it could reflect badly on the reseller.
Why would it be an issue?

I agree if they choose to underbuy bandwidth and have no site for 1/4 of the month then they either don't care or are too cheap to bother. Its not the reseller's fault. You can offer someone two products and if they choose the one that doesn't meet your needs its not your fault for not offering.

I wasn't sure if it would look like the reseller wasn't selling the right size packages to others or if it would cause any other problems for the seller. Thank you all for clarifying that for me.

It definitely isn't a big deal, I wouldn't worry about it. Honestly, I'm sure that even a lot of the big hosts probably deal with the same issue, except the ones that oversell a lot or have unlimited bandwidth. I'm kind of surprised that the customer would want that for his site, but he definitely knows how to fix that. I don't think it reflects badly on you at all, I think it just means that the customer is using a lot of bandwidth and doesn't want to upgrade.

Do not touch them if they pay for the hosting in time and fio the bandwidth extrausage as well.

EXACTLY!!! So what if they're using all the bandwidth they're paying for? A paying customer is a paying customer.

I have a couple sites that hit their bandwidth limit each month, mostly due to links from Google images. If it becomes a problem, I just go in and edit my package. That's me. Your customer might have a different budget, a different approach, or different circumstances.

And what more profitable fo you then? Moving to the other more huge package or paying extras?

You have a point there. Usually it would be on the site owners to upgrade to a higher package, if they don't reseller cannot do anything about it. However, reseller also has to make it a point to communicate this information to the site owner regarding upgrade.

Normally, it should be fine and the website might get suspended for the month. If not, and it keeps going over, then just suspend the website until the next month. And the paying customer only paid for a certain package and that customer keeps going over, so is it worth it to keep saying "Ah who cares? Better package for you for free." or "Suspended for the month".

And customer will lose the income. That is unreal. No one will agree on that.

I say just stay away from unlimited resellers

How is that the problem of the host?
If the customer is losing income then it is incumbent on them to purchase a larger plan. Why should the host take on the responsibility?

I don't see how that can be a problem with the host. The user is utilizing 100% of the resources that he paid for which is what customers are supposed to do when they purchase hosting. As long as they are suspended when they reach the limit then it's fine. The only problem is when the user isn't suspended, charged overusage fee's, and never pays those fee's.