Wrong era tv set. This one is from around 1989 or so.
The CS3505 was pre-pip board problems and pre-mass capacitor problems.

However, given the age it is very possible that some capacitors are
failing, especially in the vertical deflection circuit.

It is pretty clear that the so-called repair shop did not do a complete
job in making sure the tv was going to work properly before selling it.
If they could not provide a resolution to the problem, seems to me the
entire money should be refunded or they should come out and fix it on
site.