No, we don't offer any guarantee. But, we get the carrier-lookup information from the carriers, so the carrier data should be extremely accurate and up-to-date.

As for the SMS and MMS Gateway Addresses, we do our best to keep these up to date. However, there are some carriers we do not have the information for. In fact, a few of the smaller carriers don't even offer email-to-SMS/MMS Gateway Addresses.