How do I fix this problem?

Black lines and spots across the display are caused by damage to the LCD screen normally. You will likely need a replacement LCD screen to resolve the issue. Depending on the make and model they can be swapped pretty easily on most devices - check out YouTube for video guides showing the process. Make sure you get a quality screen from a reputable distributor - my suggestion would be to stay away from eBay, Amazon, & RepairsUniverse unless you have no other choice. These are the guys I normally use - good screens and quick service - http://www.strivemobile.com/shop-brand. They may have what you need. Good luck!

They're obviously bending you over. That's manner an excessive amount of for a realistic thermostat change. It turns out as though your mechanic did not make an effort to appropriately diagnose the exact concern with the automobile. Although thermostats do pass unhealthy, the truly concern is most likely whatever else. Further extra, in the event that they didn't bleed the air out of the cooling approach after changing the thermostat, this might rationale a no warmness trouble. You definitelyy ought to take your auto to yet another mechanic rather of those clowns. Any well mechanic could verify the temp of each heater hoses to the heater center earlier than changing the t-stat. If they noticed that one hose used to be cooler than the opposite, then that could point out a clogged heater center. In so much circumstances a heater center can also be again flushed to relief the concern with out the highly-priced alternative of it. Another feasible rationale for no warmness is a foul waterpump. I've noticeable this commonly. Sometimes a foul waterpump will drift adequate to preserve the engine from overheating, however no longer adequate to flow into by way of the heater center, hence inflicting no warmness. Good success!