Our lien is expiring and still have not received payment, Whats's our next step?

You risk losing your lien if you do not file a lawsuit to foreclose on it within 90 days of recording it. You can arrange an extension with the owner of the property you have a lien against, but that extension must be in writing and signed and usually also recorded to be valid. The most efficient and secure option is to simply file your lawsuit within the 90 days - you can always dismiss it if you and the debtor reach an agreement. To be safe, file before the 90th day - it's no fun arguing over a counting exercise when your entire lien is at stake.

I recommend you contact an attorney as soon as possible to assist you with filing the lawsuit to enforce your lien. While it can be done in pro per (aka: on your own), litigation is complex and courts are not allowed to give you a break or overlook technical deficiencies just because you do not have counsel. Generally, you will want to contact an attorney at least 30 days before a lien expires, to allow time for negotiations and drafting of the complaint, but if you do not have that much time you will probably still find an attorney that can help you.