If this is a permanent thing, then there may be grounds for SoftLayer to break the contract that they have with their ISPs. However, this will more than likely require a large number of customers complaining about this specific issue. You're the first so far.
Any changes to SoftLayer's ISP's and/or their contracts is going to negatively affect a very large amount of customers, perhaps causing extended periods of downtime, and will not be worth the risk to the company.
