4×4 S-Coss Hybrid, 4 weeks old, first small problems

I switched a bit hectic to an S-Cross Hybrid 102 HP allgrip etc. before 4 Wchen. On Friday get, on Saturday fully loaded off to Norway. 4000 km worked. Hardly back: a) tire pressure sensor left front reports no air. Access to the gas station, see there, sensor reports normal again. b) Today I want to refuel, tank cover does not jump up. Off to the workshop. Tank cover does not jump up. Mechanic tries so 5x, then he jumps up. ngel. Does anyone know that? What do I do to a Urlsubsfahrt if the tank cover does not jump up ??? Does someone have a tip? Thank you