P0148B, P20E8 codes

I bought a "fixed" "Certified Pre-Owned" 2015 Golf MKVII Sportwagen TDI about 4 months ago, (Sept, '18), with 48k miles on it from the local VW dealer. Came from S. Carolina, has extended emissions warranty until 165k miles. Have had repeated "Check Engine" and "AdBlue/engine won't start in 550 miles" lights come on. So, topped off the AdBlue, but only took about 2 cup fulls before it overflowed. The light will go off and return in about 200 miles or so. DTC code shown was P0148B. This happened repeatedly. Contacted "VW Experience" and asked about details on extended emissions warranty, they opened a case and were extremely nice and followed up on actions taken. The dealer said my diagnosis of AdBlue heater failure was correct and ordered parts, but they were "back ordered" Never called to say parts were in. After about a month "VW Experience" called me to check progress and while I held, they called dealer who said parts were in. Dealer then replaced the tank and heater, no charge. Picked up the car and got less than a mile before the "Check Engine" "AdBlue" and "Engine won't start" lights all came back on. DTC code now "P20E8" "Reductant Pressure Too Low" -3 of them! So, back to dealer in morning. Really like this car, but it's been a bit of a PIA so far

prob bad install of the new heater/plumbing, dealers try their best, let them fix it again.