It is astonishing to hear you had to wait so long for a reply from the bank!
However, I would say you should phone the bank and tell them that you expect to be put back on the tracker, and you are entitled to be put back in the same position as you were before they messed up,and as it was their fault you will not be paying any penalties for the break out fee
.I would phone them and speak to head of customer services ,and tell them if they dont do this you will proceed to the Ombudsman and that you want a final response from them in writing ,within a reasonable time ie;two weeks.
When you receive the final response, you may find they will have changed their tune,if not you should complain to the Ombudsman,and amazingly they seem to change their tune when they are notified of the receipt of a complaint and the offer of mediation from the Ombudsman.
If they don't, unfortunately you will have to wait for the Ombudsman to investigate your claim,but ( hopefully you can afford too) they will have to pay you the difference in what you are paying now and what you should have paid.
From what you have posted ,I believe you have a very strong case and I can see no reason why you should pay a penalty for their mistake..
I am in a similar position,and all penalties will be paid,I will post the details when there is a final resolution which should be within the next two weeks.
best of luck