Hey sorry to hear you have had to go through this, especially in consideration of your already stressful situation.
When you reported these issues did you take photos, confirm anything in writing and chase it up in writing with the letting agent?
As an FYI I had major issues last year with a property and (well known) agent in central Glasgow, and now the actual Landlord, from inception for the entirety of the tenancy. I took over 70 photo’s when I moved in and had nearly 50 contractors visit during the 1y tenancy… I followed everything up in writing and chased regularly (weekly, fortnightly ot monthly). Unfortunately I’d paid my tenancy upfront but some repairs took 6 months before the agent initially sent a contractor round.
If you have photographic evidence and also emails to the agent, then follow this up via their complaints procedure, bullet-pointing each complaint point so they are fully aware of your grievance. If you are unhappy with the response, escalate it but you would need to clearly explain why you are escalating (and potentially provide additional evidence or point out evidence they have missed). If you are still unhappy request a final response letter and take the agent to The Property Ombudsman. It can be quite longwinded and time consuming, but certain letting agents should not be allowed to treat tenants unfairly.
Going forward you can “withold” a percentage of your rent if repairs are taking a long time (as a last resort), but do not refuse to pay your rent. Once repairs have been completed to a reasonable standard you then pay the pecentage of rent you have witheld. You have always got the 1st tier tribunal alternative as well (which I haven’t experienced). .
My only advice would be take photos, and ensure everything is in writing (even after contractors have attended). Good luck with it, i’ll try and help if you have any other questions.