Hii,
I am willing to do this job for your company. We have a good team of experts having sound knowledge in Core PHP, mysql, integration technologies etc. I accept tht we dont have too much grip over BigComerce but i we are sure to handle your current requirement bcoz prior to place the bid, i have analysed TNT's site very well to know the exact requirements.
And to give the time-projection, i need some more details from your side. You can message me so that we can have chat related to this.
Regards:
Harshal