Client refused to pay for given website services

I am a website designer and I am giving website (domain and hosting) services to my client (a reputed hotel in vadodara, Gujarat) since 4 years. My issue is that I was renewing services every year on behalf of them on postpaid conditions because of good relations. but this time, after the renewal client fails to make payment, i have reminded about due payments on phone calls and emails but they have refused me to give payment. Now what should i do, I have temporarily suspended hosting account because of non payment, But what should I do with domain name (website name)? Can i sell that domain name to other? I haven't signed any contract with them regarding website services. but i have created a page showing "Terms and Conditions" in my website that if client fails to make payment, then domain will be fully owned by ours, will it be legally helpful?