Multiple Failures

[#1]

My broadband was supposed to be installed on 24 November 2015. This date passed so I made contact (35 minutes on phone and then hung up then 41 minutes holding on for online chat). I was told that "someone cancelled my order" so a new one would be placed with installation no later than 3 December. This date came and went without installation so I went through the tortuous process of trying to contact Plusnet once again. Times to get through were worse than before (I still haven't managed to get through to telephone support) and once again I was told that "someone had cancelled my order". A new order was promised but when I didn't get a confirmation email I made contact again. (Same delays!) Plusnet admitted that the order hadn't been placed. Blame is now being laid on my previous provider (BT) and, needless to say, they are blaming Plusnet. I have no faith in Plusnet and am wondering if I can get my money back for breach of contract?
I'm now a bit of an expert on live chat so I will pass on this tip. If, at the end of a conversation, you are offered a link to provide feedback DO NOT use it. I've been fooled twice this way after unsatisfactory service. The link goes nowhere and it means you can't rate the performance of the staff member. Ignore the link and, instead, click the "End Conversation" at the top of the Chatline screen and feel free to speak the truth.

[#2]

Hi Alan,
A warm welcome to the forums.
Just one question - did you tell BT Retail that you were ceasing service?  If the answer to that is "Yes" then that is the cause of these issues - certainly the initial ones.  A migrating user should never tell an existing supplier they are leaving as it inevitably screws up the migration.
Telling the existing supplier to end services on a given date results in a cease order being placed on the line.  Until the cease completes BTOR will not allow another order to be placed on the line - that's why PlusNet's provide orders get cancelled - not by PlusNet but by BTOR / BTw / BT Retail (in your case).
There are other situations were due to errors in BTOR's equipment databases, an order gets applied to the wrong line and the owner of that line cancels PlusNet's order.
Hope that illuminates some part of the process.  If the reason for your cancelations were different, sorry to have wasted your time. 
Kevin

[#3]

Thank you Townman. This clarifies a lot for me. It's a pity that neither Plusnet nor BT know this.
I did give notice to BT because I was on a twelve month contract and I had already received an email from them telling me that I was about to be charged for BT Sport unless I entered into a new contract which I di not want to do.