eek - nasty situation
Your phone is determining that the femotcell is preferable to your "normal" cell, and unfortunately you cannnot control the cell selection criteria of your phone, so you cannot stop your phone hopping onto the femotcell, with the unfortunate nasty side effects you have.
Moderately unhelpful thoughts that spring to mind ...
- IF (a big if) you still have good 2G coverage at home, you could (IF your phone/sim allows it) restrict your phone to "2G only" mode.
This might allow calls to become reliable then (as it won't register on the 3G femtocell) , but will it knacker any data usage you do - suboptimal at best, and probably unacceptable. And will cause problems when generally moving around as it will restrict you to the old 2G network only.
- Re 4G option (and fully appreciate the fact that you don't want to do that), but that would work
as long as you have a very solid 4G signal @ home.
If it is in any way flaky, the phone will drop back to the femtocell when it perceives the 4G signal is not good enough, so you would be back to square 1.
A la the previous thought, you might be able to lock it to 4G only, but again that will cause call reception issues (i.e. dropping out of service) if the 4G signal is flaky in the first place
and, again, will be nasty when generally moving around as it will restrict you to 4G only.
- EE giving you your own femtocell could well help by covering an area of your house with a stronger local cell signal, and your phone should prefer this. But again, if there are weak areas in the property where the neighbour's femtocell signal is stronger/better quality, the phone will register back on to your neighbours femtocell, and you are back to square 1 (proximity, building construction and the like will all have a severe impact on this scenario)
A theoretical, reliable answer is for the neighbour's femtocell to have a list of "not allowed to register" phone IMEIs so that EE could block your phone from ever registering on that "cell", but I don't think that is supported functionality....
None of the above doesn't help much I know - however, in your shoes, aside from moving networks to get away from the problem, the only thing I could think to do is to try to push EE to give you a free femtocell to see if it helps the situation, as
they have effectively changed their network footprint to your detrement ...