Rob's Renovations

I contacted Rob who gave me a quote for a complete bathroom renovation. The price quoted included the tile work (around the tub and the flooring) and the plumber whom he was subcontracting. I was supplying all of the materials necessary to complete the job. I accepted the quote which was $4,020.00 before tax. He had asked several questions prior to giving me the quote such as: is the ceiling directly beneath the bathroom accessible specifically the water lines to the tub area and a few other before giving me his quote. I do not remember if he had asked the size of the tile at that time but before beginning the job he and his tile person (only known to me as *** came to my house to go over the job. I had at some time told them that the tiles were 12" x 24" which I wanted run vertically and stacked and I had shown them where the tiles were in the garage which they saw. At that time (before construction began) I told them that since Rob would not do any electrical, I was hiring another man who would do the in floor heating as well as the other electrical such as installing the ceiling exhaust fan and relocating the vanity lighting and also told them that this man would also lay the floor tiles over the in floor heat. At no point was I told that I would be charged extra to install the tiles around the tub because the tiles were large. I was also not told that I would still have to pay Rob's Renovations for installing the floor tiles even though they were no longer doing that part of the job. They started the job, the other man came in on the weekend and installed the ceiling exhaust, relocated the vanity lighting, installed the in floor heating and the floor tiles over that heating mat. The next week Rob's Renovations came back and finished up the baseboards and whatever else was left to be completed. I believe he contacted me via text or email that very same day with the amount I owed and we made arrangements for me to leave the cheque in my mailbox. He picked up that cheque and left a receipt but I had not seen an itemized invoice at that time. About a month late I received an invoice from *** and *** for $749 and change. I contacted them to say that I had paid Rob's Renovations and they needed to collect from him. I also contacted Rob who them gave me an itemized invoice explaining how he got to his final price which is when I discovered that I was charged extra for installation of the large sized tiles and I was also charged for installing the floor tiles which were not installed by Rob or *** I was also informed that I was to pay *** and *** although I had not contracted them. An argument ensued and I continue to be hounded by email, telephone and multiple invoices in the mail by *** and *** for the $750. The price that I paid was yes indeed smaller than what was quoted but then again they also did not complete all the work that I was quoted for and I don't believe that I am liable to pay a subcontractor who was hired by Rob's Renovations.