Sealed refrigerant-circuit work, including regassing and compressor replacement, is outside this service's stated scope. A loss of cooling still needs a proper diagnosis before assuming refrigerant is the cause.
What the observation tells you
Warm food can arise from different conditions, so an internet suggestion of 'needs gas' is not a confirmed finding. If a qualified engineer has already identified a sealed-system problem, that information changes which service provider is appropriate.
A useful next step
Give the actual symptoms and any written diagnosis when enquiring. The team can clarify whether the proposed work fits its scope. Do not puncture pipework, attach recharge products or attempt to assess refrigerant by touch.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.