Calm. Blue. Ocean. :-)
Keep saying that.
I believe I did fairly well and was also expecting a call from them with the details of the next round.
"Expecting" and "going to get" are different things.
You may be assuming you'll get a call based on your own opinion of how you did, but that may not be how they saw it.
Keep an open mind on this and have fewer expectations is a good general rule.
it has now been a week since my telephone interview
They could have hundreds of interviews to perform. It might be a month for all you know.
and now I received a call from another recruiter (recruiter 'B') from the same company. She mentioned a bit about A and also asked me if I am open for relocation. I said yes and she said she'd drop an email to me with further details. It's been a day since B called me and I have still not received an email from her.
Wow. A whole day ! Seriously ?
Develop some patience.
Recruiter B was either getting some follow-up info for A or has a different role she's filling and may require relocation.
These things may require some internal discussion, and they may simply be waiting to complete a full round of interviews and contacts with other candidates before proceeding.
I would never recommend being pushy about contacting recruiters unless you were explicitly told to expect a call or email by a specific date.
And, again, drop the "expectations". They won't do anything but make you more uptight. The best running assumption to make about any interview, IMO, is that you didn't get it. That let's you get on with your life and chase other options.
One thing you do need to do is start asking questions when you're speaking with people. Part of the problem is that you did not get a clear statement from B as to why they were contacting you (instead of or on behalf of A or for a different role entirely).
You should always get a clear idea of why you are being spoken to. You need to know this to properly consider a response to any questions. For example, if I ask you if you are willing to relocate, the answer might be different depending on e.g. exactly what role you'd be relocating for, or to where, or if they give financial support for moving. Generally give an answer like "I'd be willing to consider it, but I'd need a lot more detail. Can you email me what you can about this ?".