"Abdominal mri"

Long story short, ended up few times with abdominal pain, 8 cocodamols a day, reffered for an ultrasound. Was told i have gallstones. To take pressure of NHS, paid £350 to get my mri done in Magherafelt. That scan was crucial to diagnose me and start treatment. Report came back clear, mo gallstones. Pain steady for over 3 months. Gp after seeing mri report refferef me for gastroscopy ( 4 months now and still waiting for an ultrasoung and gastroscopy). I was really worried, so flew to Poland for an ultrasound and surgeon consultation. Wow ultrasound was able to detect my gallbladder is full of stones. How is it possible that mri missed that? Flying next week for an emergency surgery. £350 wasted!