loyalty department

I have now spoken to 6 different Xfinity agents on the phone and I'm seconds from cancelling my entire service unless someone who knows what they're doing can fix this problem.  I initially spoke to an agent on Nov. 29 because I was having quality issues with my picture.  Instead of telling me to use 800+ channel numbers for HD they said I needed a new cable box and would ship one overnight with no shipping charges.  By Dec. 1, and still no box, I call back and speak to second agent.  He showed no order for the box but promised to ship one out, again no charge, overnight.  It came on Friday.  I couldn't get it working so called back Saturday Dec. 4 and the third agent said a tech would come out on Sunday the 5th (after spending at least an hour on the phone trying to figure out what was wrong).  Tech came and installed new cable box but said I really didn't need it and that all I had to do was use channels 800+ for HD.  This very valuable information was NEVER shared to me by any of the previous 3 agents I spoke with.   then I get my new bill and it is $75 more than it should be because they DID charge to ship the new cable box, then tacked on DVR monthly fee of $10, a regional sports fee of $11.61, and then somehow changed my package without my permission resulting in a higher package fee.  I called back, yet again, to talk to another agent who seemed to have it all worked out and was going to credit back those charges but needed to transfer me to another agent for finalization.  The agent he transferred me to had no idea why I was transferred to him and no clue what was going on and I had to explain myself yet again.  He then transferred me back to tech support and THAT agent had to be caught up on what was going on so I explained it for a third time.  Then after over an hour on the phone, I get disconnected and the agent didn't even have the courtesy to call me back.  Beyond frustrated at this point and seconds from going to another provider.  Unless someone who is based in the U.S. can actually salvage this relationship I will be taking my years of loyalty elsewhere.