Can I file a mechanic's lien and what do I actually get by filing one?get

I would be the General Contractor on a job in Texas. The beginning estimate on the job was $4,000. After working on the job for around 3 months a lot of extra work had been added on to the job. The $4,000 was paid with draws throughout the job. 3 days before the conclusion of the job the customer left town and I haven't seen him since. The final invoice of $3572 was sending to the customer. At this point he started claiming that we had stole some ceramic tile. We haven't heard a singke complaint from the Customer. Matter of fact he did nothing but praise the workmanship in the job. He has stated that things like tearing down a wall that he shoukdnt have to pay for the electrical because the switch was in the wall and it ran to the ceiling fan and that was on me that the ceiling fan stoped working when I tore a wall down. Basically he has came up with so many different reasons not to pay that I can't keep up with it all. The actual work performed ckukdbhsve come out to over $8,000 but I cut him a good deal and he still thinks he shouldn't pay. Should I go ahead and file for the $8,000 estimate or just take what I can get and stick to the $3572? I have already sent a letter of intent