Online services have differences from offline services. For example, user experience in using a bank website is very influencial in perceived service quality. You can find many scales to measure online service quality, including E-SERVQUAL by Parasuraman et al. which contains items addressing such different traits.
I would suggest considering the SERVPERF model, as well as analyzing the ‘desired quality’, as defined by dell’Olio, L., A. Ibeas and P. Cecin (2011). See DOI:10.1016/j.tranpol.2010.08.005