Build bathroom 30 years back on other's land claiming now

hi, we are middle class family, purchased home 30yrs back, that time bathroomwas built outside home that bathroom is not included in the paper, orally they committed with us that its ours only, from past 30yrs we are using bathroom ,but nowadays they are telling us to give that bathroom space to them because it is their paper, we have not inculded in ours paper, it come around 5*5 space, we dont have alternate choice and dont have space to built bathroom also, daily they are giving tourcher to leave bathroom space for them. kindly help us what to do..