CRC errors on ISDN Interface

I have a problem with an ISDN circuit that keeps on dropping off. When I look at the BRI interface I see CRC errors. I have swapped out the patch cable going to the providers jack, I swapped out the router and the ISDN WIC but I still keep on getting the CRC errors. The provider has checked

BRI Problem

I have 2 Cisco routers connected by 1 ISDN link between the two. Router A is setup to receive calls and Router B is setup to place the calls. What is happening is Router B makes the call but only 1 B channel is coming up. Both B channels on router B are good and I get the following Layer 1

Multiple Serial Interface

I have two switched 56 K circuits going into a Cisco 2610. Currently each serial interfaces have an IP address assigned to them. How can I bundle both interfaces together so it looks like one interface with one IP address. Thanks