First I want to tell you that you came to the right place for info. I also want to say that I think it's very wrong (and please don't take this the wrong way) for anyone to think that their Yorkie will be fully potty trained at 7 months. I am not trying to be mean but yorkies are like babies, and we all know it takes more than 7 months for human babies to get potty trained. I would suggest taking it back to the beginning, reward him when he does go and tell him no (no yelling just a stern no) when he goes on the floor. Make a big deal out of him going on the pads. It will take awhile for him to get back on track, but you just have to be patient. Georgie is just now pretty well trained and he is 11 months, but when he does have accidents I think about it like if this is the worst thing that happens life with Georgie is pretty good
Good luck and keep us posted.