just to understand your scenario:
sebvivo makes a mutant that makes lamivudine, entecavir useless, every doctor aware of hbv knows this
tenofovir is active on all mutants, and might be less potent only if q215s mutant from lamivudine is present or adefovir mutant is present so in your case it should work.you cannot stop entecavir but use a combo entecavir+tenofovir, this is called add-on and this is the only good strategy with resistance mutations
what is your hbvdna pcr on entecavir and how long did you use entecavir and sebvivo
also look for a better doctor, the one who prescribed drugs is absolutely a danger for you
your doctors are crazy and used wrong drugs from start, sabvivo is a crap drug on cirrhosis because it makes resistance and never never be used as a firstline drug on any hbv carrier
you do need a resistance test and use of a combo therapy because a resistance mutation can be deadly on cirrhosis, the best drug for you is tenofovir+entecavir combination and you should monitor creatinine from start and then every week first month and if no rise every month
since you started with sabivo you might have resistant mutants and the only drug active on all mutants is tenofovir, the use of entecavir combo will prevent any resistance and make the tretment very safe and potent