If few respondents do not receive court letters

I filled a civil suit. Total 5 respondents are there. Among them 3 received court summons but other 2 willingly not taking letter . When Post man reached their home, those two hiding themselves and their family members informed that they are now at home. Post man tried twice and court letter returned back. My advocate advised me at anyhow letter should be received by them otherwise case will get long delay. Is it so? Please share the member's views.