Did you ever notice that if there's a bad connection, the person you're talking to ALWAYS blames you & your phone? I suppose if I can hear perfectly & you can't, I might assume it's your phone, but that doesn't even make sense: It's not the phone, it's between us & sometimes it just happens. They are always very judgmental: You're moving around - hold still! Something's wrong with your phone! Not only is it your fault, they know what you are doing to cause or exacerbate it.
How about: "We seem to have a bad connection. Let me try calling you right back."
I remember many, many years ago, when Maggie & Rachel lived on 9th St, we were on the phone & we could hear another conversation, faint but clear. We started butting in, giving girlfriend advice, until they realized what we were doing. They lived nearby & somehow we ended up meeting up at the Grassroots. Nelson & Rene were Puerto Rican revolutionaries & eventually moved to Boston, but we hung out for a few months.