Specialist in lavarel programming needed - debug & small changes

We have a custom made CRM and the system has some minor bugs which have to be repaired - uploading files in some part of the CRM are uploaded, afterwards some dissapear and others cannot be opened..

The system also requires some changes.

Please only professionals with experience and capable freelancer(NO people which intermediates other people service). We have allready had 3 person here which completely distroyed the CRM and we are not beeing amused by this.
Payment will only be given free at the end. No payment upfront, we allready payed 3 people and they did nothing and we payed for nothing.

IMPORTANT: We have a strict deadline, if our software is destroyed the person is directly responsabile for that - and will come up for all costs.