international call fees

I am absolutely disgusted by a $2.49 charge on my bill this month for "international call fees."  First of all, I never made any international calls.  Second, if someone did call me, there is NO WAY to tell that this is an international incoming call - but I get charged for picking up the phone for my business?  This is outrageous to me!  If you are going to charge me for an international incoming call, there MUST be a way to indicate that ahead of time - a voice saying, this is an international call, do you accept the charges?  Would work!  Because I will say no every time!  Better yet - allow me to block any and all international incoming calls for my business!  But just to slam me with a fee for picking up the phone having no idea that they are international - that is unfair, in this new business owner's opinion and SHOULD NOT BE ALLOWED!  Furthermore, when I went to look at the call log - there wasn't even an unrecognized call or number listed - so who was this mystery person I don't even know I spoke to?  When I called customer service to have it removed, they were INCREDIBLY RUDE - accusing me of making calls or knowingly accept the call - and then they said I can let them go to voicemail -and NOT get charged, but in my business - putting someone in voicemail can very likely loose the client - FIX THIS PLEASE COMCAST and fix it quickly!