Legal fees

Hey, so recently (February) me any my partner parted ways. We share a son together and she has stopped me being able to see him and refused contact blocking me everywhere. I tried to seek legal advice costing me over 300 to do so. Then the solicitor told me that in order to start the court process I needed 1700. Now being a single father (I have a 6 year old daughter) this is funds I physically cannot raise. All I want is to be able to see my son and have that bond with him and so does his sister. It’s hitting us both in different ways and this is mainly for the children that I ask for this help if I can get them seeing eachother at least then that would be a win in my books. Thank you all who help out with this I appreciate everyone