Would I be assuming any liability by signing a letter that includes the following:"In light of the way this working relationship proceeded and ended, there will have to beadjustments on the final invoice. Your performance has cost us time, money and reputation, thusMNB IT Services Inc. (formerly(NNN) NNN-NNNNOntario Inc. o/a M&B Services) (“MNB”) will be making anadjustment against this invoice to recuperate some of the losses."
Province/Territory relating to question: Ontario
That phrase will not in and of itself expose you to liability.
But adjusting the invoice could give rise to a lawsuit because the person who invoiced you will take the position that you are not paying what you owe.
That is not to say you are wrong and if you are sued you can prove your position in Court.
The letter is addressed to me, they are adjusting my invoice.
So you can sue them if you feel that you are entitled to the money.They cannot decide what to pay you at their discretion.But if there concerns hold some merit it may be most prudent to try and work out a solution outside of Court.